How to Create A Full Stack Multi-Step Registration App with nice animations using the MERN Stack

In this article, we will build an amazing Multi Step Registration form with smooth animated transitions using MERN(MongoDB, Express, React, Node.js) stack.

By building this App, you will learn a lot of concepts in react including:

How to manage data for multiple forms with validation for each field
How to retain values of forms data across routes
How to update progress indication for each registration step
How to load country-specific state and city from the API
How to create smooth sliding animation using a very popular framer-motion library
How to create Rest APIs using Express.js
How to implement login and registration functionality with MongoDB
How to store and validate password in encrypted form in MongoDB

And much more.

We will be using React Hooks syntax for building this application in React. So if you're new to React Hooks, check out my Introduction to React Hooks article to learn the basics of Hooks.

We will also be using the MongoDB database to store the user entered data so make sure you install the MongoDB database locally by following instructions from this article.

So let’s get started.

Initial Project Setup

Create a new project using create-react-app

npx create-react-app multi-step-form-using-mern

Once the project is created, delete all files from the src folder and create index.js file and styles.scss file inside the src folder. Also create components, router, and utils folders inside the src folder.

Install the necessary dependencies:

yarn add axios@0.21.1 bootstrap@4.6.0 react-bootstrap@1.5.0 country-state-city@2.0.0 framer-motion@3.7.0 node-sass@4.14.1 react-hook-form@6.15.4 react-router-dom@5.2.0 sweetalert2@10.15.5

Open styles.scss file and add the contents from here inside it.

We'll use SCSS syntax to write CSS. So if you're new to SCSS, check out my this article for an introduction to it.

How to Create the Initial Pages

Create a new file Header.js inside the components folder with the following content:

import React from 'react';

const Header = () => (
  <div>
    <h1>Multi Step Registration</h1>
  </div>
);

export default Header;

Create a new file FirstStep.js inside the components folder with the following content:

import React from 'react';

const FirstStep = () => {
  return (
    <div>
      First Step Form
    </div>
  )
};

export default FirstStep;

Create a new file AppRouter.js inside the router folder with the following content:

import React from 'react';
import { BrowserRouter, Route, Switch } from 'react-router-dom';
import FirstStep from '../components/FirstStep';
import Header from '../components/Header';

const AppRouter = () => (
  <BrowserRouter>
    <div className="container">
      <Header />
      <Switch>
        <Route component={FirstStep} path="/" exact={true} />
      </Switch>
    </div>
  </BrowserRouter>
);

export default AppRouter;

In this file, initially, we have added a single route for the first step.

If you're new to React Router, check out my free Introduction to React Router course.

Now, open the src/index.js file and add the following contents inside it:

import React from 'react';
import ReactDOM from 'react-dom';
import AppRouter from './router/AppRouter';
import 'bootstrap/dist/css/bootstrap.min.css';
import './styles.scss';

ReactDOM.render(<AppRouter />, document.getElementById('root'));

Now, start the application by running the yarn start command and you will see the following screen:

Initial Screen

How to Add Progress Steps in the Header

Create a new file Progress.js inside the components folder with the following content:

import React from 'react';

const Progress = () => {
  return (
    <React.Fragment>
      <div className="steps">
        <div className="step">
          <div>1</div>
          <div>Step 1</div>
        </div>
        <div className="step">
          <div>2</div>
          <div>Step 2</div>
        </div>
        <div className="step">
          <div>3</div>
          <div>Step 3</div>
        </div>
      </div>
    </React.Fragment>
  );
};

export default Progress;

and use it inside the Header.js file as shown below:

import React from 'react';
import Progress from './Progress';

const Header = () => (
  <div>
    <h1>Multi Step Registration</h1>
    <Progress />
  </div>
);

export default Header;

Now, If you check the application, you will see the following screen:

With Progress

How to Create the First Step Form

Now, let's add the form for the first step.

Open components/FirstStep.js file and replace it with the following contents:

import React from 'react';
import { useForm } from 'react-hook-form';
import { Form, Button } from 'react-bootstrap';

const FirstStep = (props) => {
  const { register, handleSubmit, errors } = useForm();

  const onSubmit = (data) => {
    console.log(data);
  };

  return (
    <Form className="input-form" onSubmit={handleSubmit(onSubmit)}>
      <div className="col-md-6 offset-md-3">
        <Form.Group controlId="first_name">
          <Form.Label>First Name</Form.Label>
          <Form.Control
            type="text"
            name="first_name"
            placeholder="Enter your first name"
            autoComplete="off"
            ref={register({
              required: 'First name is required.',
              pattern: {
                value: /^[a-zA-Z]+$/,
                message: 'First name should contain only characters.'
              }
            })}
            className={`${errors.first_name ? 'input-error' : ''}`}
          />
          {errors.first_name && (
            <p className="errorMsg">{errors.first_name.message}</p>
          )}
        </Form.Group>

        <Form.Group controlId="last_name">
          <Form.Label>Last Name</Form.Label>
          <Form.Control
            type="text"
            name="last_name"
            placeholder="Enter your last name"
            autoComplete="off"
            ref={register({
              required: 'Last name is required.',
              pattern: {
                value: /^[a-zA-Z]+$/,
                message: 'Last name should contain only characters.'
              }
            })}
            className={`${errors.last_name ? 'input-error' : ''}`}
          />
          {errors.last_name && (
            <p className="errorMsg">{errors.last_name.message}</p>
          )}
        </Form.Group>

        <Button variant="primary" type="submit">
          Next
        </Button>
      </div>
    </Form>
  );
};

export default FirstStep;

Here, we're using a very popular react-hook-form library to easily manage forms with validations.

React-hook-form makes it really easy to work with simple as well as complex forms as we don't need to manage the state of each input field and its onChange handler ourselves which makes the code clean and easy to understand.

Check out my this article to learn about react-hook-form in detail.

As can be seen in the above code, to use the react-hook-form library we need to first import and use the useForm hook.

  const { register, handleSubmit, errors } = useForm();

Here,

register is a function to be used as a ref provided by the useForm hook. We can assign it to each input field so that the react-hook-form can track the changes for the input field value
handleSubmit is the function we can call when the form is submitted
errors will contain the validation errors, if any

In the above code, we have given a ref to each input field that we got from the useForm hook like this:

ref={register({
  required: 'First name is required.',
  pattern: {
    value: /^[a-zA-Z]+$/,
    message: 'First name should contain only characters.'
  }
})}

Also, we added the onSubmit function which is passed to the handleSubmit function.

<Form className="input-form" onSubmit={handleSubmit(onSubmit)}>

Note that for each input field, we have given a unique name which is mandatory so react-hook-form can track the changing data.

When we submit the form, the handleSubmit function will handle the form submission. It will send the user entered data to the onSubmit function which we’re logging to the console.

const onSubmit = (data) => {  
 console.log(data);
};

If there are any errors, we're displaying it like this:

{errors.first_name && (
  <p className="errorMsg">{errors.first_name.message}</p>
)}

The errors object will be automatically populated with the property name denoted by the name given to each input field, If there is any error. first_name in the above case is the name given to the first input field.

Now, let's check the application functionality.

First Step Form

As you can see with very little code, we've added a responsive validation functionality to the form.

How to Create the Second Step Form

Now, create a new file SecondStep.js inside the components folder with the following content:

import React from 'react';
import { useForm } from 'react-hook-form';
import { Form, Button } from 'react-bootstrap';

const SecondStep = (props) => {
  const { register, handleSubmit, errors } = useForm();

  const onSubmit = (data) => {
    console.log(data);
  };

  return (
    <Form className="input-form" onSubmit={handleSubmit(onSubmit)}>
      <div className="col-md-6 offset-md-3">
        <Form.Group controlId="first_name">
          <Form.Label>Email</Form.Label>
          <Form.Control
            type="email"
            name="user_email"
            placeholder="Enter your email address"
            autoComplete="off"
            ref={register({
              required: 'Email is required.',
              pattern: {
                value: /^[^@ ]+@[^@ ]+\.[^@ .]{2,}$/,
                message: 'Email is not valid.'
              }
            })}
            className={`${errors.user_email ? 'input-error' : ''}`}
          />
          {errors.user_email && (
            <p className="errorMsg">{errors.user_email.message}</p>
          )}
        </Form.Group>

        <Form.Group controlId="password">
          <Form.Label>Password</Form.Label>
          <Form.Control
            type="password"
            name="user_password"
            placeholder="Choose a password"
            autoComplete="off"
            ref={register({
              required: 'Password is required.',
              minLength: {
                value: 6,
                message: 'Password should have at-least 6 characters.'
              }
            })}
            className={`${errors.user_password ? 'input-error' : ''}`}
          />
          {errors.user_password && (
            <p className="errorMsg">{errors.user_password.message}</p>
          )}
        </Form.Group>

        <Button variant="primary" type="submit">
          Next
        </Button>
      </div>
    </Form>
  );
};

export default SecondStep;

Now, let's add another route in AppRouter.js file for the SecondStep component.

import React from 'react';
import { BrowserRouter, Route, Switch } from 'react-router-dom';
import FirstStep from '../components/FirstStep';
import Header from '../components/Header';
import SecondStep from '../components/SecondStep';

const AppRouter = () => (
  <BrowserRouter>
    <div className="container">
      <Header />
      <Switch>
        <Route component={FirstStep} path="/" exact={true} />
        <Route component={SecondStep} path="/second" />
      </Switch>
    </div>
  </BrowserRouter>
);

export default AppRouter;

Also, import the SecondStep component at the top of the file as shown above.

Now, we've added a route for the second step, let's check the application by accessing the URL http://localhost:3000/second.

Second Step Form

As you can see, the functionality is working fine but we're directly accessing the /second route. Instead, let's add the code to programmatically redirect from step 1 to step 2.

When we provide any component for the Route inside the BrowserRouter, the React router automatically passes 3 props to that component which are:

history
location and
match

Out of these, the history object contains a push method that we can use to redirect from one component to another.

So open FirstStep.js file and replace the onSubmit function with the following code:

const onSubmit = (data) => {
    console.log(data);
    props.history.push('/second');
  };

Here, for the push method, we've provided the route to which we need to redirect.

Redirection

As you can see, when we click on the Next button in the first step we're redirected to the second step.

Now, create a new file constants.js inside the utils folder with the following content:

export const BASE_API_URL = 'http://localhost:3030';

Here, we're specifying our backend API URL. So we don't need to specify it in every API call. We just need to use this constant when we need to make an API call.

Now, let's add another route in AppRouter.js file for the ThirdStep component.

...
<Switch>
  <Route component={FirstStep} path="/" exact={true} />
  <Route component={SecondStep} path="/second" />
  <Route component={ThirdStep} path="/third" />
</Switch>
...

How to Get a List of All Countries from the API

Create a new file ThirdStep.js file inside the components folder with the following content:

import React, { useState, useEffect } from 'react';
import { Form, Button } from 'react-bootstrap';
import csc from 'country-state-city';
import axios from 'axios';
import { BASE_API_URL } from '../utils/constants';

const ThirdStep = (props) => {
  const [countries, setCountries] = useState([]);
  const [states, setStates] = useState([]);
  const [cities, setCities] = useState([]);
  const [isLoading, setIsLoading] = useState(false);

  const [selectedCountry, setSelectedCountry] = useState('');
  const [selectedState, setSelectedState] = useState('');
  const [selectedCity, setSelectedCity] = useState('');

  useEffect(() => {
   const getCountries = async () => {
     try {
       const result = await csc.getAllCountries();
       console.log(result);
     } catch (error) {}
    };

    getCountries();
  }, []);

  const handleSubmit = async (event) => {
    event.preventDefault();
  };

  return (
    <Form className="input-form" onSubmit={handleSubmit}>
      <div className="col-md-6 offset-md-3"></div>
    </Form>
  );
};

export default ThirdStep;

In this file, we're using a country-state-city npm library to get a list of available countries, cities and states like this:

import csc from 'country-state-city';

Then in the component, we've defined some states:

const [countries, setCountries] = useState([]);
const [states, setStates] = useState([]);
const [cities, setCities] = useState([]);
const [isLoading, setIsLoading] = useState(false);

const [selectedCountry, setSelectedCountry] = useState('');
const [selectedState, setSelectedState] = useState('');
const [selectedCity, setSelectedCity] = useState('');

Here, countries, states and cities are declared in the state that will store the list of countries, states and cities respectively coming from the API.

Another isLoading state is added for keeping track of when the data is loading. selectedCountry, selectedState and selectedCity will contain the selected value when the user selects a particular dropdown value.

Then we've added a useEffect hook to make an API call to get the list of countries as shown below:

useEffect(() => {
  ...
  const result = await csc.getAllCountries();
  ...
}, []);

Here, we're calling the getAllCountries method of country-state-city library to get a list of available countries. Note that, we've passed an empty array [] as the second argument to the useEffect hook so the hook will be called only once when the component is mounted.

Now, open SecondStep.js file and replace the onSubmit function with the following code:

const onSubmit = (data) => {
    console.log(data);
    props.history.push('/third');
};

Using this code, we can easily navigate to the ThirdStep component.

Now, let's check the application.

Countries log

As you can see, on the component load, we're getting a list of available countries in an array of objects.

Each object contains an isoCode and name property that we can use in our code to display it on the screen.

So change the useEffect hook to the below code:

useEffect(() => {
  const getCountries = async () => {
    try {
      setIsLoading(true);
      const result = await csc.getAllCountries();
      let allCountries = [];
      allCountries = result?.map(({ isoCode, name }) => ({
        isoCode,
        name
      }));
      const [{ isoCode: firstCountry } = {}] = allCountries;
      setCountries(allCountries);
      setSelectedCountry(firstCountry);
      setIsLoading(false);
    } catch (error) {
      setCountries([]);
      setIsLoading(false);
    }
  };

  getCountries();
}, []);

Here, we're first setting the isLoading flag to true to indicate that data is loading which we will use soon.

Each object of the array contains many other properties like phonecode, flag, currency etc but we only want isoCode and name so we're using the array map method to filter out only those properties as shown below:

allCountries = result?.map(({ isoCode, name }) => ({
  isoCode,
  name
}));

Here, we're using the ES11 optional chaining operator which is denoted by ? so code after ? will be executed only if the previous reference is not undefined or null. And as we're destructuring isoCode and name, the optional chaining operator is required.

The optional chaining operator is very useful in many scenarios. Understand it in detail in Mastering Modern JavaScript book.

Then we've the following code:

const [{ isoCode: firstCountry } = {}] = allCountries;
setCountries(allCountries);
setSelectedCountry(firstCountry);
setIsLoading(false);

Let's understand what we're doing here.

Here, we've used object destructuring renaming with assignment syntax. We're destructuring the isoCode property from the first object of the allCountries array of objects and renaming the isoCode property to firstCountry just to identify that it's the first country from the list. we're also assigning a default empty object so If the allCountries array is empty we'll not get an error.

In short, we are saying, take the isoCode property from the first object from the allCountries array of objects and rename it to firstCountry . If the firstCountry property does not exist in the first object from the allCountries array then assign a default value of empty object {} to the firstCountry variable.

Then we're updating the selectedCountry state value to the firstCountry value and isLoading state value to false using the below code:

setSelectedCountry(firstCountry);
setIsLoading(false);

Now, in the ThirdStep.js file, change the following code:

return (
  <Form className="input-form" onSubmit={handleSubmit}>
    <div className="col-md-6 offset-md-3"></div>
  </Form>
);

to this code:

return (
    <Form className="input-form" onSubmit={handleSubmit}>
      <div className="col-md-6 offset-md-3">
        <Form.Group controlId="country">
          {isLoading && (
            <p className="loading">Loading countries. Please wait...</p>
          )}
          <Form.Label>Country</Form.Label>
          <Form.Control
            as="select"
            name="country"
            value={selectedCountry}
            onChange={(event) => setSelectedCountry(event.target.value)}
          >
            {countries.map(({ isoCode, name }) => (
              <option value={isoCode} key={isoCode}>
                {name}
              </option>
            ))}
          </Form.Control>
        </Form.Group>
      </div>
    </Form>
  );

So we can see the list of countries populated in the dropdown.

Now, If you navigate to step 3, you will see the following screen:

Country Populate

As you can see, the country dropdown is correctly populated with all countries and on change of the dropdown value, the selectedCountry state is also changing to the country code(isoCode) as can be seen in the react dev tools.

How to Get a List of States from the API

Now, let's add the code for getting a list of states based on the selected country.

Add the following code after the first useEffect hook in the ThirdStep.js file.

useEffect(() => {
    const getStates = async () => {
      try {
        const result = await csc.getStatesOfCountry(selectedCountry);
        let allStates = [];
        allStates = result?.map(({ isoCode, name }) => ({
          isoCode,
          name
        }));
        console.log({ allStates });
        const [{ isoCode: firstState = '' } = {}] = allStates;
        setCities([]);
        setSelectedCity('');
        setStates(allStates);
        setSelectedState(firstState);
      } catch (error) {
        setStates([]);
        setCities([]);
        setSelectedCity('');
      }
    };

    getStates();
  }, [selectedCountry]);

Here, we're calling the getStatesOfCountry method from the country-state-city library by passing the selectedCountry as the parameter and based on the result of the API, we're updating the respective states as shown below:

setCities([]);
setSelectedCity('');
setStates(allStates);
setSelectedState(firstState);

All the country, state and city dropdowns are inter-related so If we're changing the country, we should update the state also which we're doing in the above code.

Also, note that we've passed the selectedCountry as a second parameter to the useEffect hook in the dependencies array:

useEffect(() => {
 ...
}, [selectedCountry]);

So this effect will only run when the selectedCountry state will change which means that once we change the country dropdown, we're making an API call to get the states related to only that country and then populating the state dropdown values.

Now, add the following code after the first Form.Group closing tag that is after the country dropdown:

<Form.Group controlId="state">
  <Form.Label>State</Form.Label>
  <Form.Control
    as="select"
    name="state"
    value={selectedState}
    onChange={(event) => setSelectedState(event.target.value)}
  >
    {states.length > 0 ? (
      states.map(({ isoCode, name }) => (
        <option value={isoCode} key={isoCode}>
          {name}
        </option>
      ))
    ) : (
      <option value="" key="">
        No state found
      </option>
    )}
  </Form.Control>
</Form.Group>

Here, we're displaying the state dropdown on the screen and If there are no states for the selected country, we're showing No state found message because there are some countries that don't have any state.

Now, If you check the application, you will see the following screen:

State Populate

As can be seen above, when we change the country dropdown value, the state dropdown list is also updated based on the selected country.

How to Get a List of Cities from the API

Now, let's populate the cities based on country and state value.

Add another useEffect hook after the second hook as shown below:

useEffect(() => {
  const getCities = async () => {
    try {
      const result = await csc.getCitiesOfState(
        selectedCountry,
        selectedState
      );
      let allCities = [];
      allCities = result?.map(({ name }) => ({
        name
      }));
      const [{ name: firstCity = '' } = {}] = allCities;
      setCities(allCities);
      setSelectedCity(firstCity);
    } catch (error) {
      setCities([]);
    }
  };

  getCities();
}, [selectedState]);

Here, we're calling the getCitiesOfState method from the country-state-city library by passing the selectedCountry and selectedState as parameters and based on the result of the API, we're updating the cities dropdown.

Now, add the following code after the second Form.Group closing tag that is after the state dropdown:

<Form.Group controlId="city">
  <Form.Label>City</Form.Label>
  <Form.Control
    as="select"
    name="city"
    value={selectedCity}
    onChange={(event) => setSelectedCity(event.target.value)}
  >
    {cities.length > 0 ? (
      cities.map(({ name }) => (
        <option value={name} key={name}>
          {name}
        </option>
      ))
    ) : (
      <option value="">No cities found</option>
    )}
  </Form.Control>
</Form.Group>

Here, we're displaying the cities dropdown on the screen and If there are no cities for the selected state, we're showing No cities found message because there are some states that don't have any cities.

Now, If you check the application, you will see the following screen:

City Populate

As can be seen above, on change of country and state, the corresponding list of cities is populated in the cities dropdown.

Also, add the Register button after the last Form.Group closing tag that is after the city dropdown:

<Button variant="primary" type="submit">
  Register
</Button>

Now, your screen will look like this:

Last Step

Now, we're done with screens of all the steps, let's get the steps progress in the header working so it's clear on which step we're currently on.

How to Add a Progress Indicator in the Header

We're showing the Progress component inside the Header component but Progress component is not mentioned in any of the Route in the AppRouter.js file neither Header is mentioned in the Route. So by default, we don't have access to the history, location and match props in both the Header and Progress components to identify which route we're on.

But there is an easy way to fix it. React Router provides a withRouter component which we can use in the Progress component so we will get access to the history, location and match props.

Open Progress.js file and add import for the withRouter component at the top of the file:

import { withRouter } from 'react-router-dom';

and change the export statement from this code:

export default Progress;

to this code:

export default withRouter(Progress);

So when we pass Progress component to the withRouter component we'll get access to the history, location and match props inside the Progress component.

Now, replace the Progress component with the following code:

const Progress = ({ location: { pathname } }) => {
  const isFirstStep = pathname === '/';
  const isSecondStep = pathname === '/second';
  const isThirdStep = pathname === '/third';

  return (
    <React.Fragment>
      <div className="steps">
        <div className={`${isFirstStep ? 'step active' : 'step'}`}>
          <div>1</div>
          <div>
            {isSecondStep || isThirdStep ? (
              <Link to="/">Step 1</Link>
            ) : (
              'Step 1'
            )}
          </div>
        </div>
        <div className={`${isSecondStep ? 'step active' : 'step'}`}>
          <div>2</div>
          <div>{isThirdStep ? <Link to="/second">Step 2</Link> : 'Step 2'}</div>
        </div>
        <div className={`${pathname === '/third' ? 'step active' : 'step'}`}>
          <div>3</div>
          <div>Step 3</div>
        </div>
      </div>
    </React.Fragment>
  );
};

Here, in the first line, we're destructuring the location property from the props object and then pathname property from the location property in a single line like this:

const Progress = ({ location: { pathname } }) => {

and based on which route we're on, we're adding the active class to each step div.

Also, import the Link component at the top of the file:

import { Link, withRouter } from 'react-router-dom';

Now, If you check the application, you will see the following screen:

Working Progress

As you can see, when we're on a particular step, that step number is shown as active in the progress bar with the highlighted text and as we navigate through the steps, the text of the previous steps is shown as a link so we can navigate back to any step to change any data.

How to Retain Entered Data Across Routes

But you will notice that, when we goto step 1 by clicking the link from step 3, the entered data of step 1 is lost.

This is because when we go from one route to another route, React Router completely unmounts the previous route component and mounts the next route component connected to that route so all the state values are lost.

So let's add a way to preserve the entered data when navigating to the previous step.

As you know, only the components connected to the routes mentioned in the AppRouter.js file are mounted and unmounted on the route change but the AppRouter component in our case is not unmounted even when the routes change so the best place to store the data entered by the user is the AppRouter component.

Let's add the user state, updateUser and resetUser functions inside the AppRouter.js file.

const [user, setUser] = useState({});

const updateUser = (data) => {
  setUser((prevUser) => ({ ...prevUser, ...data }));
};

const resetUser = () => {
  setUser({});
};

So we will store the user-entered data in each step in the user state which is an object.

In the updateUser function, we're passing data to update the user state. In the updateUser function, we're first spreading out the user object values using the prevUser variable and then spreading out the data object so the resulting object will be merging of two objects.

For updating the state, we're using the updater syntax of state with implicit return syntax for object.

So this code:

setUser((prevUser) => ({ ...prevUser, ...data }));

is the same as below code:

setUser((prevUser) => {
  return {
    ...prevUser,
    ...data
  };
});

As can be seen above, If we want to implicitly return an object from an arrow function, we can skip the return keyword and enclose the object in a round bracket.

This will make the code shorter and will also avoid typing mistakes in your code so you will find most React code is written using implicit return syntax.

So If we're in step 1 then we will pass the {first_name: 'Mike', last_name: 'Jordan' } as data and add it to the user state.

Then in the step 2, If we pass {user_email: 'test@example.com', user_password: 'test@123'} as the data, then the updateUser function will update the user as shown below:

const prevUser = { first_name: 'Mike', last_name: 'Jordan' };
const data = { user_email: 'test@example.com', user_password: 'test@123' };

const result = { ...prevUser, ...data };
console.log(result); // { first_name: 'Mike', last_name: 'Jordan', user_email: 'test@example.com', user_password: 'test@123' }

Now, we have created the user state, updateUser function, we need to pass it to each route that is connected to the step so we can save the user-entered data by calling the updateUser function.

Our current routes in AppRouter.js file looks like this:

<Switch>
  <Route component={FirstStep} path="/" exact={true} />
  <Route component={SecondStep} path="/second" />
  <Route component={ThirdStep} path="/third" />
</Switch>

So to pass the user and updateUser as a prop to the components connected to the route we can't pass it like this:

<Route component={FirstStep} path="/" exact={true} user={user} updateUser={updateUser} />

Because this way props will be passed to the Route and not to the FirstStep component. So we need to use the following syntax:

<Route
  render={(props) => (
    <FirstStep {...props} user={user} updateUser={updateUser} />
  )}
  path="/"
  exact={true}
/>

Here, we're using render props pattern for passing the props. This will correctly pass the props as well as it will not re-create the FirstStep component on every re-render.

You can check out my Introduction to React Router course to learn more about why we need to use render instead of component prop.

Now, after making this change for all the steps related routes, your routes will look like this:

<BrowserRouter>
  <div className="container">
    <Header />
    <Switch>
      <Route
        render={(props) => (
          <FirstStep {...props} user={user} updateUser={updateUser} />
        )}
        path="/"
        exact={true}
      />
      <Route
        render={(props) => (
          <SecondStep {...props} user={user} updateUser={updateUser} />
        )}
        path="/second"
      />
      <Route
        render={(props) => (
          <ThirdStep {...props} user={user}  />
        )}
        path="/third"
      />
    </Switch>
  </div>
</BrowserRouter>

Note that, we're not passing the updateUser prop to the ThirdStep component route because when we submit the form from step 3 we will be saving all the data directly into the database.

If you want you can pass the updateUser function to the ThirdStep component and save it to the state by calling the updateUser function but it's not necessary.

Now, let's use the updateUser function inside these components to save the data.

So open FirstStep.js and SecondStep.js files and inside the onSubmit handler function, add props.updateUser(data) as the first statement.

// FirstStep.js
const onSubmit = (data) => {
  props.updateUser(data);
  props.history.push('/second');
};

// SecondStep.js
const onSubmit = (data) => {
  props.updateUser(data);
  props.history.push('/third');
};

Now, If you check the application, you will see the following screen:

Saving To State

As you can see, Initially AppRouter component state is an empty object but when we submit form in each step, the state object gets updated with the user-entered data.

Now, let's use that data saved in the state and populate in the respective input fields when we come back to the previous step from the next step.

As you know, we're using react-hook-form to manage the changing data of the forms in FirstStep and SecondStep component using the useForm hook.

But the useForm hook also takes an optional parameter which we can use to persist the values across route change.

So change the below code from FirstStep.js file:

const { register, handleSubmit, errors } = useForm();

to this code:

const { user } = props;
const { register, handleSubmit, errors } = useForm({
  defaultValues: {
    first_name: user.first_name,
    last_name: user.last_name
  }
});

Here, we're destructuring the user prop from the props object which we're passing in the route of AppRouter.js file and then we're using the defaultValues property to set the value for each input field.

Just to remind, first_name and last_name are the names given to the input fields in FirstStep component which are used by react-hook-form for tracking changing data.

Now, If you check the application, you will see the following screen:

Data Retained

As you can see, when we come back from step 2 to step 1, the data entered in step 1 is not lost as we're re-setting it with the data from the user state when the component is mounted again on route change.

Now, let's add the similar code in SecondStep.js file also:

const { user } = props;
const { register, handleSubmit, errors } = useForm({
  defaultValues: {
    user_email: user.user_email,
    user_password: user.user_password
  }
});

Now, If you check the application, you will see the following screen:

Data Retained Step 2

As you can see, when we come back from step 3 to step 2 or step 1, the data entered in step 1 and step 2 is not lost. So we have successfully preserved the data across steps.

How to Add Animated Transitions to the App

Now, let's add a smooth sliding animation functionality to the app.

For adding animation we're using a very popular framer motion library.

Framer motion makes it very easy to add animation using a declarative approach just like React way of doing things.

So let's add animation in the FirstStep component.

Open FirstStep.js file and add the import statement for the framer motion library at the top of the file:

import { motion } from 'framer-motion';

To animate any element on the page, we need to prefix it with motion like this:

<div>Click here to animate it</div>

// the above code will need to be converted to

<motion.div>Click here to animate it</motion.div>

Using motion as a prefix will return a React component that has specific animating capabilities added so we can pass props to that element.

So inside the FirstStep.js file, after adding the motion prefix to the following div:

<div className="col-md-6 offset-md-3">
...
</div>

it will look like this:

<motion.div className="col-md-6 offset-md-3">
...
</motion.div>

Once we add a motion prefix to it, we can provide extra props to that element like this:

<motion.div
  className="col-md-6 offset-md-3"
  initial={{ x: '-100vw' }}
  animate={{ x: 0 }}
>
...
</motion.div>

Here, we've provided an initial prop to specify the location from where the animation will begin. We want the entire form to be slid in from the left side so we provided the x value as -100vw which means 100% viewport width from the left side. So the initial position of the form will be far left but not visible on the screen.

Then we provided animate prop with x value of 0 so the form will slide in from left and will come back to it's original position on the page. If we provide the value of 10 for x then it will move to 10px on the right side from its original position.

Now, your entire JSX code in FirstStep.js file will look like this:

return (
  <Form className="input-form" onSubmit={handleSubmit(onSubmit)}>
    <motion.div
      className="col-md-6 offset-md-3"
      initial={{ x: '-100vw' }}
      animate={{ x: 0 }}
    >
      <Form.Group controlId="first_name">
        <Form.Label>First Name</Form.Label>
        <Form.Control
          type="text"
          name="first_name"
          placeholder="Enter your first name"
          autoComplete="off"
          ref={register({
            required: 'First name is required.',
            pattern: {
              value: /^[a-zA-Z]+$/,
              message: 'First name should contain only characters.'
            }
          })}
          className={`${errors.first_name ? 'input-error' : ''}`}
        />
        {errors.first_name && (
          <p className="errorMsg">{errors.first_name.message}</p>
        )}
      </Form.Group>

      <Form.Group controlId="last_name">
        <Form.Label>Last Name</Form.Label>
        <Form.Control
          type="text"
          name="last_name"
          placeholder="Enter your last name"
          autoComplete="off"
          ref={register({
            required: 'Last name is required.',
            pattern: {
              value: /^[a-zA-Z]+$/,
              message: 'Last name should contain only characters.'
            }
          })}
          className={`${errors.last_name ? 'input-error' : ''}`}
        />
        {errors.last_name && (
          <p className="errorMsg">{errors.last_name.message}</p>
        )}
      </Form.Group>

      <Button variant="primary" type="submit">
        Next
      </Button>
    </motion.div>
  </Form>
);

Now, If you check the application, you will see the sliding animation on page load:

Sliding Animation

As you can see, the form is slided in from the left side of the page but it does not yet look so smooth yet.

To make it a smooth animation, we can provide an additional transition prop in addition to the initial and animate prop.

<motion.div
  className="col-md-6 offset-md-3"
  initial={{ x: '-100vw' }}
  animate={{ x: 0 }}
  transition={{ stiffness: 150 }}
>
...
</motion.div>

Here, we've added a transition prop with value of 150 for stiffness. You can try changing the value from 150 to something else and check which one looks best to you. I will use 150 here.

Now, If you check the application, you will see a smooth sliding animation on page load:

Smooth Animation

Let's make the same animation changes in SecondStep.js and ThirdStep.js files:

import { motion } from 'framer-motion';
...
<motion.div
  className="col-md-6 offset-md-3"
  initial={{ x: '-100vw' }}
  animate={{ x: 0 }}
  transition={{ stiffness: 150 }}
>
...
</motion.div>

Now, If you check the application, you will see a smooth sliding animation on page load for all the 3 steps:

All Steps Animation

How to Setup the Backend with Node.js

Now, we're done with all the basic functionality of the front-end. Let's setup backend server code so we can save the data entered in the form to the MongoDB database.

Create a new folder with the name server outside the src folder and create models, routers folders inside the server folder.

Now, execute the following command from the server folder from the command line:

yarn init -y

This will create a package.json file inside the server folder so we can manage the dependencies.

Now, Install the required dependencies by executing the following command from the server folder from terminal:

yarn add bcryptjs@2.4.3 cors@2.8.5 express@4.17.1 mongoose@5.11.18 nodemon@2.0.7

Now, create a new file with the name .gitignore inside the server folder and add the following line inside it so the node_modules folder will not be pushed to GitHub If you decide to push your code to GitHub.

node_modules

Create a new file db.js inside the server folder with the following content:

const mongoose = require('mongoose');

mongoose.connect('mongodb://127.0.0.1:27017/form-user', {
  useNewUrlParser: true,
  useCreateIndex: true,
  useUnifiedTopology: true
});

Here, we're using mongoose library to work with MongoDB. For the mongoose.connect method, we've provided a connection string with the form-user database as the name of the database.

You can give whatever name you want instead of form-user.

Now, create a new file with the name index.js inside the server folder and add the following contents inside it:

const express = require('express');
require('./db');

const app = express();
const PORT = process.env.PORT || 3030;

app.get('/', (req, res) => {
  res.send('<h2>This is from index.js file</h2>');
});

app.listen(PORT, () => {
  console.log(`server started on port ${PORT}`);
});

Now, open server/package.json file and add the scripts section inside it:

"scripts": {
    "start": "nodemon index.js"
},

Here we're using nodemon npm package that will restart the express server If any change is made in index.js or files included in the index.js file so we don't have to manually restart the server on every change.

So your entire package.json file will look like this:

{
  "name": "server",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "scripts": {
    "start": "nodemon index.js"
  },
  "dependencies": {
    "bcryptjs": "2.4.3",
    "cors": "2.8.5",
    "express": "4.17.1",
    "mongoose": "5.11.18",
    "nodemon": "2.0.7"
  }
}

Now, open another terminal and execute the yarn start command from inside the server folder.

If you access http://localhost:3030/, you will see the following screen:

Server Initial Page

This shows that our express server is correctly set up. Let's write Rest APIs to store the user registration data.

How to Create the REST APIs

Create a new file user.js inside server/models folder with the following content:

const mongoose = require('mongoose');

const userSchema = mongoose.Schema(
  {
    first_name: {
      type: String,
      required: true,
      trim: true
    },
    last_name: {
      type: String,
      required: true,
      trim: true
    },
    user_email: {
      type: String,
      required: true,
      trim: true,
      validate(value) {
        if (!value.match(/^[^@ ]+@[^@ ]+\.[^@ .]{2,}$/)) {
          throw new Error('Email is not valid.');
        }
      }
    },
    user_password: {
      type: String,
      required: true,
      trim: true,
      minlength: 6
    },
    country: {
      type: String,
      required: true,
      trim: true
    },
    state: {
      type: String,
      trim: true
    },
    city: {
      type: String,
      trim: true
    }
  },
  {
    timestamps: true
  }
);

const User = mongoose.model('User', userSchema);

module.exports = User;

Here, we've created a User schema to define the structure of the data stored in the User collection.

If you have never worked with mongoose library then check out my this article for an introduction.

Create a new file user.js inside the routers folder with the following content:

const express = require('express');
const User = require('../models/user');
const bcrypt = require('bcryptjs');
const router = express.Router();

router.post('/register', async (req, res) => {
  const { user_email, user_password } = req.body;

  console.log('req.body', req.body);

  let user = await User.findOne({ user_email });
  if (user) {
    return res.status(400).send('User with the provided email already exist.');
  }

  try {
    user = new User(req.body);
    user.user_password = await bcrypt.hash(user_password, 8);

    await user.save();
    res.status(201).send();
  } catch (e) {
    res.status(500).send('Something went wrong. Try again later.');
  }
});

module.exports = router;

Here, we've created a post API for the /register route. We will be passing the data to this API in JSON format and the express server makes it available inside req.body object so we're destructuring the email and password value from it:

const { user_email, user_password } = req.body;

Then using the findOne method of the User model, we're first checking If there is any user with the provided email address.

  let user = await User.findOne({ user_email });

If such a user exists, then we're returning an error back to the client(which is our React App).

return res.status(400).send('User with the provided email already exist.');

It's always good to specify the HTTP response code of the error while sending back the response.

You can find all HTTP status codes and their meaning on this website.

Then we're passing all the user data like first_name, last_name, user_email, users_password, country, state and city which is present in the req.body to the User constructor .

But we don't want to store the user-entered data into the database as it is so we're using a very popular bcryptjs npm library to hash the password before saving it to the database.

user.user_password = await bcrypt.hash(user_password, 8);

Check out my this article to learn about bcryptjs in details.

And once the password is hashed, we're calling the save method of User model to save all the details along with hashed password into the MongoDB database.

await user.save();

Once we're done, we're sending back the response with the status code of 201 which described that something is created.

res.status(201).send();

Note that, here we're not sending back any data but just a response saying that the request is successful and a new record was created.

Then at the end, we're exporting the express router so we can use it in the index.js file.

Now, open server/index.js file and import the user router at the top of the file:

const userRouter = require('./routers/user');

As we're sending the data to register from React app to Node.js server in JSON format, we need to add the following code for a middleware:

app.use(express.json());

Also, after the PORT constant, add the following line of code:

app.use(userRouter);

So your entire server/index.js file will look like this:

const express = require('express');
const userRouter = require('./routers/user');
require('./db');

const app = express();
const PORT = process.env.PORT || 3030;

app.use(express.json());
app.use(userRouter);

app.get('/', (req, res) => {
  res.send('<h2>This is from index.js file</h2>');
});

app.listen(PORT, () => {
  console.log(`server started on port ${PORT}`);
});

Here, we've provided userRouter as a middleware for the express app. So we can make API requests to it.

It's always good to separate out each router in its own file and include it using the app.use method to avoid making the code larger by writing it in a single file.

Now, start your local MongoDB database server by running ./mongod --dbpath=<path_to_mongodb-data_folder> command as explained in this article and keep it running.

And then restart the express server by running yarn start command from the server folder and keep it running.

Open another terminal and start the react app by running yarn start command If not already done.

So now you will two separate terminals open - one for running the express server app and another one running the react app as shown below.

VSCode Terminals

Here, we're opening terminals inside the VSCode. You can open first terminal by going to the Terminal -> New Terminal menu of VS Code and then just click the + icon to open additional terminals.

How to Call REST APIs from a React App

Now, let's make the code changes in our React app to make the API call to our /register API.

Open ThirdStep.js file and replace the handleSubmit method with the following code:

const handleSubmit = async (event) => {
    event.preventDefault();

    try {
      const { user } = props;
      const updatedData = {
        country: countries.find(
          (country) => country.isoCode === selectedCountry
        )?.name,
        state:
          states.find((state) => state.isoCode === selectedState)?.name || '',
        city: selectedCity
      };

      await axios.post(`${BASE_API_URL}/register`, {
        ...user,
        ...updatedData
      });
    } catch (error) {
      if (error.response) {
        console.log('error', error.response.data);
      }
    }
  };

Here, once we submit the form in step 2, we're calling the handleSubmit method where we're making an API call to our /register API:

await axios.post(`${BASE_API_URL}/register`, {
  ...user,
  ...updatedData
});

Here, we're passing the data to the /register API in the JSON format.

As we're storing the country code in selectedCountry and state code in selectedState state variables which are denoted by isoCode, we're first using the array find method to find out the actual names related to that country and state code as shown below:

const updatedData = {
  country: countries.find(
    (country) => country.isoCode === selectedCountry
  )?.name,
  state:
    states.find((state) => state.isoCode === selectedState)?.name || '',
  city: selectedCity
};

If you want a quick refresher on the most widely used array methods including array find method, check out my this article.

Inside selectedCity state variable we're storing the name so we don't need to use the filter method there.

While using the find method for state, we've added || condition because If there is no available state for any selected country, then while accessing ?.name, it might come as undefined so to avoid storing undefined in the database, we're using the || operator to store an empty string '' instead or undefind.

How to Test REST APIs

Now, let's check the application functionality.

CORS Error

As you can see, when we try to submit the form in the step 3, we're getting CORS(Cross-Origin Resource Sharing) error in the browser console.

This is because the browser does not allow accessing data of application running on another port because we are running react application on port 3000 and Node.js application on port 3030.

This is for security reasons and due to cross-domain policy.

So to fix this, we need to install the cors npm package and use it in our server/index.js file so the Node.js server will allow any application to access its APIs.

Don’t worry, we will see how we can use the Node.js APIs without using cors later in this article and it will also avoid the need of running two separate terminals for starting React and Node.js server.

So, for now, open server/index.js file and add the import for cors as shown below:

const cors = require('cors');

Note that we've already installed the cors npm package while creating the express server earlier.

And add it as an express middleware before the app.use(userRouter) statement like this:

app.use(express.json());
app.use(cors());
app.use(userRouter);

Now your index.js file will look like this:

const express = require('express');
const cors = require('cors');
const userRouter = require('./routers/user');
require('./db');

const app = express();
const PORT = process.env.PORT || 3030;

app.use(express.json());
app.use(cors());
app.use(userRouter);

app.get('/', (req, res) => {
  res.send('<h2>This is from index.js file</h2>');
});

app.listen(PORT, () => {
  console.log(`server started on port ${PORT}`);
});

Now, If you submit the form, you will correctly see the data logged into the console:

Save Log

And the data also gets saved into the database as shown below:

Saved Into DB

So now, we've successfully connected our front-end React app to the back-end Node.js app and saved the data into the database.

One thing you might have noticed is that we're not showing any indication that the data is successfully saved to the database once we register the user. So let's do that now.

For showing the success message, we'll use sweetalert2 which is a very popular customizable popup modal library.

Import it in the ThirdStep.js file as shown below:

import Swal from 'sweetalert2';

and inside the handleSubmit function, after the axios.post call, add the following code in the try block:

Swal.fire('Awesome!', "You're successfully registered!", 'success').then(
(result) => {
  if (result.isConfirmed || result.isDismissed) {
    props.history.push('/');
  }
}
);

and in the catch block add the following code:

if (error.response) {
  Swal.fire({
    icon: 'error',
    title: 'Oops...',
    text: error.response.data
  });
}

So your handleSubmit function will look like this now:

const handleSubmit = async (event) => {
    event.preventDefault();

    try {
      const { user } = props;
      const updatedData = {
        country: countries.find(
          (country) => country.isoCode === selectedCountry
        )?.name,
        state:
          states.find((state) => state.isoCode === selectedState)?.name || '', // or condition added because selectedState might come as undefined
        city: selectedCity
      };

      await axios.post(`${BASE_API_URL}/register`, {
        ...user,
        ...updatedData
      });
      Swal.fire('Awesome!', "You're successfully registered!", 'success').then(
        (result) => {
          if (result.isConfirmed || result.isDismissed) {
            props.history.push('/');
          }
        }
      );
    } catch (error) {
      if (error.response) {
        Swal.fire({
          icon: 'error',
          title: 'Oops...',
          text: error.response.data
        });
        console.log('error', error.response.data);
      }
    }
  };

Now, If you check the application, you will see the following screen:

Email Error

As you can see, If the user with the email address already exists in the database then we're showing an error message from the catch block.

And If the user email does not exist in the database, then we see the success popup as can be seen below:

Success Register

If you check the code of popup for success, it looks like this:

Swal.fire('Awesome!', "You're successfully registered!", 'success').then(
  (result) => {
    if (result.isConfirmed || result.isDismissed) {
      props.history.push('/');
    }
  }
);

So If the user clicks on the OK button or clicks outside the popup modal we're redirecting the user to step 1 using props.history.push('/');. But we also should clear the user-entered data from the input fields once the registration is successful. So let's do that.

If you remember, we have added a resetUser function inside the AppRouter component to clear the user state data.

Let's pass this function as a prop to the ThirdStep component. So your ThirdStep route will look like this:

<Route
  render={(props) => (
    <ThirdStep
      {...props}
      user={user}
      updateUser={updateUser}
      resetUser={resetUser}
    />
  )}
  path="/third"
/>

And inside the handleSubmit function of ThirdStep.js file, before calling props.history.push('/'); call the resetUser function like this:

Swal.fire('Awesome!', "You're successfully registered!", 'success').then(
  (result) => {
    if (result.isConfirmed || result.isDismissed) {
      props.resetUser();
      props.history.push('/');
    }
  }
);

Now, If you register a new user, you will see that after registration, you will be redirected to the step 1 and all the input fields will also be cleared.

Cleared Fields

We have added the entire registration functionality for front-end and back-end. Let's add login functionality so we can check If the user with provided email and password exists and then retrieve the details of that user.

Open the routers/user.js file and add the following code inside it before the module.exports statement.

router.post('/login', async (req, res) => {
  try {
    const user = await User.findOne({ user_email: req.body.user_email });
    if (!user) {
      return res.status(400).send('User with provided email does not exist.');
    }

    const isMatch = await bcrypt.compare(
      req.body.user_password,
      user.user_password
    );

    if (!isMatch) {
      return res.status(400).send('Invalid credentials.');
    }
    const { user_password, ...rest } = user.toObject();

    return res.send(rest);
  } catch (error) {
    return res.status(500).send('Something went wrong. Try again later.');
  }
});

Here, we're first checking If the user with provided email already exists using the findOne method. If no such user exists then we're returning back an error with a status code of 400.

If there is a user with the provided email address then we're using bcrypt.compare method to compare the original non-hashed password with the hashed password. If the hashed converted password does not match with the password from the user object, then we're returning an error saying Invalid credentials.

But If the password matches then we're creating a new rest object with all the user properties except the hashed password using the ES9 rest operator for objects:

const { user_password, ...rest } = user.toObject();

This is because we don't want to return back the hashed password for security reasons.

And then we will send back the rest object with the password removed back to the client(our React app).

Now, we've created the back-end API, let's integrate the front-end part for login functionality.

Create a new file Login.js inside components folder with the following code:

import React, { useState } from 'react';
import { useForm } from 'react-hook-form';
import { Form, Button } from 'react-bootstrap';
import axios from 'axios';
import { BASE_API_URL } from '../utils/constants';

const Login = () => {
  const { register, handleSubmit, errors } = useForm();
  const [successMessage, setSuccessMessage] = useState('');
  const [errorMessage, setErrorMessage] = useState('');
  const [userDetails, setUserDetails] = useState('');

  const onSubmit = async (data) => {
    console.log(data);

    try {
      const response = await axios.post(`${BASE_API_URL}/login`, data);
      setSuccessMessage('User with the provided credentials found.');
      setErrorMessage('');
      setUserDetails(response.data);
    } catch (error) {
      console.log(error);
      if (error.response) {
        console.log('error', error.response.data);
        setErrorMessage(error.response.data);
      }
    }
  };

  return (
    <Form className="input-form" onSubmit={handleSubmit(onSubmit)}>
      <div className="col-md-6 offset-md-3">
        {errorMessage ? (
          <p className="errorMsg login-error">{errorMessage}</p>
        ) : (
          <div>
            <p className="successMsg">{successMessage}</p>

            {userDetails && (
              <div className="user-details">
                <p>Following are the user details:</p>
                <div>First name: {userDetails.first_name}</div>
                <div>Last name: {userDetails.last_name}</div>
                <div>Email: {userDetails.user_email}</div>
                <div>Country: {userDetails.country}</div>
                <div>State: {userDetails.state}</div>
                <div>City: {userDetails.city}</div>
              </div>
            )}
          </div>
        )}
        <Form.Group controlId="first_name">
          <Form.Label>Email</Form.Label>
          <Form.Control
            type="email"
            name="user_email"
            placeholder="Enter your email address"
            ref={register({
              required: 'Email is required.',
              pattern: {
                value: /^[^@ ]+@[^@ ]+\.[^@ .]{2,}$/,
                message: 'Email is not valid.'
              }
            })}
            className={`${errors.user_email ? 'input-error' : ''}`}
          />
          {errors.user_email && (
            <p className="errorMsg">{errors.user_email.message}</p>
          )}
        </Form.Group>

        <Form.Group controlId="password">
          <Form.Label>Password</Form.Label>
          <Form.Control
            type="password"
            name="user_password"
            placeholder="Choose a password"
            ref={register({
              required: 'Password is required.',
              minLength: {
                value: 6,
                message: 'Password should have at-least 6 characters.'
              }
            })}
            className={`${errors.user_password ? 'input-error' : ''}`}
          />
          {errors.user_password && (
            <p className="errorMsg">{errors.user_password.message}</p>
          )}
        </Form.Group>

        <Button variant="primary" type="submit">
          Check Login
        </Button>
      </div>
    </Form>
  );
};

export default Login;

Now, open AppRouter.js file and add a route for Login at the end of all routes before the ending Switch tag like this:

<BrowserRouter>
     ...
    <Route component={Login} path="/login" />
    </Switch>
  </div>
</BrowserRouter>

Also, include the Login component at the top:

import Login from '../components/Login';

Now, If you access http://localhost:3000/login, you will see the following screen:

Here, we actually don't need to show the steps in the header, so let's add a condition to hide it on the login page.

Open Progress.js file and add another const variable like this:

const isLoginPage = pathname === '/login';

And add a ternary operator condition before the start of div with class steps:

<React.Fragment>
  {!isLoginPage ? (
    <div className="steps">
     ...
    </div>
  ) : (
    <div></div>
  )}
</React.Fragment>

So If the page is not a login page, then we'll display the steps otherwise we will display an empty div.

Note that we need to render an empty div If we don't have anything to render because React will throw an error If we don't return any JSX from the component.

Your entire Progress.js file will look like this now:

import React from 'react';
import { Link, withRouter } from 'react-router-dom';

const Progress = ({ location: { pathname } }) => {
  const isFirstStep = pathname === '/';
  const isSecondStep = pathname === '/second';
  const isThirdStep = pathname === '/third';
  const isLoginPage = pathname === '/login';

  return (
    <React.Fragment>
      {!isLoginPage ? (
        <div className="steps">
          <div className={`${isFirstStep ? 'step active' : 'step'}`}>
            <div>1</div>
            <div>
              {isSecondStep || isThirdStep ? (
                <Link to="/">Step 1</Link>
              ) : (
                'Step 1'
              )}
            </div>
          </div>
          <div className={`${isSecondStep ? 'step active' : 'step'}`}>
            <div>2</div>
            <div>
              {isThirdStep ? <Link to="/second">Step 2</Link> : 'Step 2'}
            </div>
          </div>
          <div className={`${pathname === '/third' ? 'step active' : 'step'}`}>
            <div>3</div>
            <div>Step 3</div>
          </div>
        </div>
      ) : (
        <div></div>
      )}
    </React.Fragment>
  );
};

export default withRouter(Progress);

Now, If you check the login page, you will see the page without steps in the header but the steps will be displayed for other pages.

And If you enter the correct login credentials then you will get the details related to that user as shown below:

If the login credentials are invalid, you will see the error message as shown below:

Invalid Login

If the email exists but the password does not match then you will see the error message as shown below:

Invalid Credentials

Now, let's understand the code from Login.js file:

const onSubmit = async (data) => {
  console.log(data);

  try {
    const response = await axios.post(`${BASE_API_URL}/login`, data);
    setSuccessMessage('User with the provided credentials found.');
    setErrorMessage('');
    setUserDetails(response.data);
  } catch (error) {
    console.log(error);
    if (error.response) {
      console.log('error', error.response.data);
      setErrorMessage(error.response.data);
    }
  }
};

In the onSubmit function, we're making an API call to the /login endpoint by passing the data entered in the login form.

If there is no error in the API response, we will set the successMessage state and set the userDetails state with the response from the API otherwise we will set the errorMessage state.

And in the JSX, if the errorMessage state is not empty, we'll display the error message otherwise display successMessage state value with the userDetails data:

{errorMessage ? (
  <p className="errorMsg login-error">{errorMessage}</p>
) : (
  <div>
    <p className="successMsg">{successMessage}</p>

    {userDetails && (
      <div className="user-details">
        <p>Following are the user details:</p>
        <div>First name: {userDetails.first_name}</div>
        <div>Last name: {userDetails.last_name}</div>
        <div>Email: {userDetails.user_email}</div>
        <div>Country: {userDetails.country}</div>
        <div>State: {userDetails.state}</div>
        <div>City: {userDetails.city}</div>
      </div>
    )}
  </div>
)}

Note that we have not provided a link for the login page on the screen because the application is for displaying multi-step form functionality. I have included the login page so you will get an idea of how to validate the user login.

If you want, you can include the login page link in the header or directly access it using http://localhost:3000/login.

How to Setup an Invalid Route Page

Now, we've done with the entire functionality of the App. Let's add some code so If we enter any invalid route in the browser URL, we should redirect the user back to the home page.

Currently, If you access any invalid route like http://localhost:3000/contact, you will see a blank page and there is also no error in the console because there is no matching route in the list of routes inside the AppRouter.js file.

Blank Page

So, open AppRouter.js file and after the login route, enter another route as shown below:

  ...
  <Route component={Login} path="/login" />
  <Route render={() => <Redirect to="/" />} />
</Switch>

Here, we've not provided any path to the Route component for the last Route so If any of the above routes do not match, this last Route will be executed which will redirect the user to the / route which is FirstPage component route.

Also, import the Redirect component from the react-router-dom at the top of the file:

import { BrowserRouter, Redirect, Route, Switch } from 'react-router-dom';

Note that, you need to enter it as the last route only so If any of the above routes do not match, the last route will be executed and it will redirect to the home page.

Let's verify it now.

Page Not Found

As you can see, for all invalid routes, we're redirected to the home page which is the first step page.

How to Get Rid of the CORS Library

As you know, to run this application, we need to start our React app using yarn start command in one terminal and we also need to execute yarn start command from the server folder for the backend server and we also need to keep our MongoDB server running in the third terminal.

So let's avoid the need of running two separate yarn start commands. This will also allow you to deploy your app on single hosting provider.

If you remember, in the server/index.js file, we added the following code:

app.use(cors());

Adding this code allows any application to access our APIs which is fine when working in a local environment but it's not safe to allow everyone to access our APIs. So let's fix it.

Open server/index.js file and add the below code just above the app.use(express.json()); line:

app.use(express.static(path.join(__dirname, '..', 'build')));

Here, we're configuring our express app to use the contents of the build folder as a starting point of our app.

The build folder will be created when we run the yarn build command for our React app.

As the build folder will be created outside the server folder, we're using .. to come out of the server folder to access it.

Also, import the path node package at the top of the file:

const path = require('path');

We don't need to install the path npm package, it's added by default when we install Node.js on our system.

Now, you can remove the cors import and its use from the server/index.js file.

Your final server/index.js file will look like this now:

const path = require('path');
const express = require('express');
const userRouter = require('./routers/user');
require('./db');

const app = express();
const PORT = process.env.PORT || 3030;

app.use(express.static(path.join(__dirname, '..', 'build')));
app.use(express.json());
app.use(userRouter);

app.get('/', (req, res) => {
  res.send('<h2>This is from index.js file</h2>');
});

app.listen(PORT, () => {
  console.log(`server started on port ${PORT}`);
});

Now stop both the yarn start commands from both the terminals and only in one terminal execute yarn build command from inside the multi-step-form-using-mern folder which is our project folder.

The yarn build command will take some time to complete as it performs some optimizations and it should only be executed when we're done with all the app functionality and when we're ready to deploy the app to production.

Build Completed

Once the command completes successfully, you will see a build folder created as shown below:

File Structure

The build folder contains our entire React App so you can use this build folder to deploy our app to production.

Now, open src/utils/constants.js file and replace this code:

export const BASE_API_URL = 'http://localhost:3030';

with the below code:

export const BASE_API_URL = '';

Now, as we've created the build folder, navigate to server folder from the terminal and execute the yarn start command:

Server Started

As you can see, the server is started on port 3030.

So let's access our application at http://localhost:3030/.

Complete Flow

As you can see, we only need to run one yarn start command to start the Node.js express server. The Node.js server renders our React app on port 3030 from the build folder.

So all our APIs are available now on http://localhost:3030 such as http://localhost:3030/register and http://localhost:3030/login.

Therefore we have changed the BASE_API_URL value to just an empty string:

export const BASE_API_URL = '';

So when we're already on http://localhost:3030 we can make all our POST request APIs using just /login and /register.

So we only need one terminal to run the yarn start command and another terminal for starting the MongoDB service and so we can deploy our app on single hosting provider like heroku instead of deploying React app on one hosting provider and Node.js app on another Hosting provider.

Note that, If you make any changes to the React app code, you will need to re-run the yarn build command from the project folder and then yarn start command from the server folder.

But there is one issue with this setup. If you directly go to any route apart from the / route like /first, /second, /login etc, you will get an error as can be seen below:

Error

This is because we’re starting server from Express.js so the request will always go to the Express.js server(our Node server created using Express.js) and there is no /second route for handling that at Node.js side. So it gives an error.

So to fix this, open server/index.js file and before the app.listen statement and after all other routes, add the following code:

app.use((req, res, next) => {
  res.sendFile(path.join(__dirname, '..', 'build', 'index.html'));
});

So this code will act as a default route and If any of the previous routes do not match, this code will send back the index.html file from the build folder which is our React app.

And because the /second route is present in our React app, you will see the correct step 2 page.

If the entered route is not present on Node.js app as well as in our React app, then you will be redirected to the step 1 page which is our home page of the app because of our last route in the AppRouter.js file.

<Route render={() => <Redirect to="/" />} />

So your complete server/index.js file will look like this:

const path = require('path');
const express = require('express');
const userRouter = require('./routers/user');
require('./db');

const app = express();
const PORT = process.env.PORT || 3030;

app.use(express.static(path.join(__dirname, '..', 'build')));
app.use(express.json());
app.use(userRouter);

app.get('/', (req, res) => {
  res.send('<h2>This is from index.js file</h2>');
});

app.use((req, res, next) => {
  res.sendFile(path.join(__dirname, '..', 'build', 'index.html'));
});

app.listen(PORT, () => {
  console.log(`server started on port ${PORT}`);
});

And you will not get an error now:

Error Fixed

If you want to learn in-depth about rendering React app using Node.js, check out my this article.

So now, we're done with both the front-end and back-end functionality as can be seen below:

Complete Working App

Closing points

We're done building out the functionality of the App.

You can find the complete GitHub source code for this application in this repository.

To take your skills further, you can improve the application by adding extra validation at the step 3 to check If the user has entered all the details in the form. Because you can directly visit the second step page of the form by using http://localhost:3030/second and proceed from there.

Thanks for reading!

Want to learn all ES6+ features in detail including let and const, promises, various promise methods, array and object destructuring, arrow functions, async/await, import and export and a whole lot more from scratch?

Check out my Mastering Modern JavaScript book. This book covers all the pre-requisites for learning React and helps you to become better at JavaScript and React.

Due to a lot of requests for decreasing the price of the book, I'm running a discount sale so you can get the book at just $13 only for today. So don't miss this opportunity.

Also, you can check out my free Introduction to React Router course to learn React Router from scratch.

Want to stay up to date with regular content regarding JavaScript, React, Node.js? Follow me on LinkedIn.

How to Create A Full Stack Multi-Step Registration App with nice animations using the MERN Stack

Comments (1)

More from this blog

How to Build a Task Management App Using Next.js 16 and Prisma 7

React's/Next.js Worst Week Ever! Just Got Worse

React Performance Anti-Patterns: 5 Mistakes That Kill Your App's Speed!

How to Access Both Company and Personal GitHub Repositories On The Same Machine

How to Build Multi-Language React Apps with Internationalization (i18n)

Initial Project Setup

How to Create the Initial Pages

How to Add Progress Steps in the Header

How to Create the First Step Form

How to Create the Second Step Form

How to Get a List of All Countries from the API

How to Get a List of States from the API

How to Get a List of Cities from the API

How to Add a Progress Indicator in the Header

How to Retain Entered Data Across Routes

How to Add Animated Transitions to the App

How to Setup the Backend with Node.js

How to Create the REST APIs

How to Call REST APIs from a React App

How to Test REST APIs

How to Setup an Invalid Route Page

How to Get Rid of the CORS Library

Closing points

Thanks for reading!

Command Palette

Comments (1)

More from this blog

Initial Project Setup

How to Create the Initial Pages

How to Add Progress Steps in the Header

How to Create the First Step Form

How to Create the Second Step Form

How to Get a List of All Countries from the API

How to Get a List of States from the API

How to Get a List of Cities from the API

How to Add a Progress Indicator in the Header

How to Retain Entered Data Across Routes

How to Add Animated Transitions to the App

How to Setup the Backend with Node.js

How to Create the REST APIs

How to Call REST APIs from a React App

How to Test REST APIs

How to Show the Registration Feedback Popup

How to Add Login Functionality to the App

How to Test the Login Functionality

How to Setup an Invalid Route Page

How to Get Rid of the CORS Library

Closing points

Thanks for reading!