Course Introduction

How to Setup a React Developer Environment with nvm

Intro & Dev Environment Setup

Module 1 Introduction

What is an API?

Okay, but what is a REST API?

What is Express? The Basics of the Node.js web framework

The Basics of Express Router - Requests and Responses

Getting Started with REST APIs & Express

Module 2 Introduction

Getting Started with the Spotify Developer Dashboard

Add nodemon to an Express App to Restart Node Automatically

What is OAuth and How Does it Work? [with examples]

How to Implement OAuth Flow in Express and Node.js

Authentication & Authorization with Spotify

Module 3 Introduction

How to Pass OAuth Tokens to a React App

Optimize React and Express.js code with npm concurrently

Setting Up a React Front-End

Module 4 Introduction

Using Local Storage to Persist Login State

How to Fetch Spotify API Data with Credentials with Axios

How to Setup and Scaffold React Router

Beginner's Guide to Styled Components in React [with examples]

Login State & Front-End Scaffolding

Module 5 Introduction

How to Build a Login Page in React

How to Build a Profile Page in React with Spotify API Data

How to Build a Spotify Top Artists & Top Tracks Page in React

How to Build a Spotify Playlists Page in React

How to Build a Spotify Individual Playlist Page in React

How to Build a React Loading Animation Component

Building & Styling the UI

Module 6 Introduction

How to Change Your React Favicon and Social Preview Images

How to Deploy React to Heroku With a Node.js Server

How to Add a README.md File to React

Deploying to the Internet

Wrapping Up What We’ve Learned

Course Wrap Up

node.js

express

axios

dotenv

Have you ever been curious to see what your Spotify data looks like? How a round-up of your listening habits gets compiled every year? Or even wanted to see metadata of your favorite tracks? Luckily, Spotify makes a ton of interesting data like this accessible via the Spotify API. For example, there is data available for every users’ [top tracks and artists](https://developer.spotify.com/documentation/web-api/reference/#endpoint-get-users-top-artists-and-tracks) of all time and [audio features](https://developer.spotify.com/documentation/web-api/reference/#endpoint-get-several-audio-features) like danceability and tempo for every single track.

## Why this course

If you're interested in accessing personalized Spotify data like we mentioned above, Spotify requires your app to be authorized. And to get authorization, you'll need to implement something called OAuth. This course will walk you through every step of the OAuth flow in a concise, easy to follow way. Unlike YouTube tutorials that only cover a few concepts and leave you with half-baked GitHub repositories, we'll cover everything from explaining what REST APIs are to implementing Spotify's OAuth flow to fetching data from the Spotify API in React hooks. Split into seven modules, each lesson includes clear, detailed explanations and complete code examples. By the end of the course, you'll have an app deployed to the internet that you can share with your friends and add to your portfolio.

## What we’ll build

**On the front end**, we’ll build out a professional, responsive user interface with [React](https://reactjs.org/), React Hooks, and the popular CSS-in-JS library, [Styled Components](https://styled-components.com/). We’ll pull in data from the Spotify API using modern ES6 [async/await](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous/Async_await) methods and display that data in an engaging way.

**On the back end**, we’ll learn the basics of [REST APIs](https://en.wikipedia.org/wiki/Representational_state_transfer), [HTTP requests](https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods), and [OAuth](https://oauth.net/). We'll lift the veil on how to [authorize an app with Spotify](https://developer.spotify.com/documentation/general/guides/authorization-guide/), and then build a Node server with the [Express framework](https://expressjs.com/) to handle our authentication requests. Finally, we’ll deploy our app to the internet using [Heroku](https://www.heroku.com/).

![Top Artists](https://d2uusema5elisf.cloudfront.net/courses/build-a-spotify-connected-app/module_00/lesson_00.00/public/assets/screenshot-1.png)

![Top Tracks](https://d2uusema5elisf.cloudfront.net/courses/build-a-spotify-connected-app/module_00/lesson_00.00/public/assets/screenshot-2.png)

![Playlist tracks sorted by tempo](https://d2uusema5elisf.cloudfront.net/courses/build-a-spotify-connected-app/module_00/lesson_00.00/public/assets/screenshot-3.png)

Learn how to build a full stack web app to visualize personalized Spotify data with the help of Node.js, React, Styled Components, and the Spotify Web API.

Build a Spotify Connected App

Principles of REST APIs and how they relate to the Spotify API

How to implement the Spotify OAuth flow with JavaScript

How to use local storage to store auth tokens

How to fetch data from the Spotify API in a React app

How to handle async code with React hooks and async/await

How to efficiently style an app with Styled Components

How to deploy an app with a React front-end and Node.js back-end to Heroku

Since we're now running two apps simultaneously (the front end React app and the back end Express app), we have two 

 files. This means that to have our front end and back end up and running we need to make sure we've run 

 directory. In this lesson, we'll go over a few things we can do to optimize our development workflow with this setup.

What if we wanted to make an HTTP request from our React app to one of our Express app's endpoints? A good example would be when our access token expires, and we need to get a new one with the 

. Usually, when you encounter CORS errors, it's because you are trying to access resources from another domain (i.e. 

), and the domain you're requesting resources from is not permitted.

To tell the development server to proxy any unknown requests to our API server in development, we can simply set up a 

Now, if we set up a request to our Express app's 

, we should see some JSON data in addition to the tokens printed in our console.

  useEffect(() => {
    const queryString = window.location.search;
    const urlParams = new URLSearchParams(queryString);
    const accessToken = urlParams.get('access_token');
    const refreshToken = urlParams.get('refresh_token');

    console.log(accessToken);
    console.log(refreshToken);

    if (refreshToken) {
      fetch(`/refresh_token?refresh_token=${refreshToken}`)
        .then(res => res.json())
        .then(data => console.log(data))
        .catch(err => console.error(err));
    }
  }, []);

Another improvement we can make to our development workflow is adding a build tool to let us run multiple npm commands at the same time. To do this, we'll add an npm package called 

---
title: Optimize React and Express.js code with npm concurrently
description: Streamline development in a client/server architecture with Concurrently
privateVideoUrl: https://fullstack.wistia.com/medias/pyy9pathor
isPublicLesson: true
---

Since we're now running two apps simultaneously (the front end React app and the back end Express app), we have two `package.json` files. This means that to have our front end and back end up and running we need to make sure we've run `npm install` and `npm start` in _both_ the root of the project _and_ in the `client` directory. In this lesson, we'll go over a few things we can do to optimize our development workflow with this setup.

## Proxying API requests

What if we wanted to make an HTTP request from our React app to one of our Express app's endpoints? A good example would be when our access token expires, and we need to get a new one with the `/refresh_token` endpoint we set up.

If we tried to send a GET request to `http://localhost:8888/refresh_token` from `http://localhost:3000`, we would run into CORS issues.

![CORS error](https://d2uusema5elisf.cloudfront.net/courses/build-a-spotify-connected-app/module_03/lesson_03.02/public/assets/cors-error.png)

CORS stands for [Cross-Origin Resource Sharing](https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS). Usually, when you encounter CORS errors, it's because you are trying to access resources from another domain (i.e. <http://localhost:3000> and <http://localhost:8888>), and the domain you're requesting resources from is not permitted.

To tell the development server to proxy any unknown requests to our API server in development, we can simply set up a [proxy](https://create-react-app.dev/docs/proxying-api-requests-in-development/) in our React app's `package.json` file. In `client/package.json`, let's add a proxy for <http://localhost:8888> (where our Express app runs).

```json { actualFilename=./protected/src/client/package.json endLine=5 startLine=5 statedFilename=client/package.json url=https&#x3A;//gitlab.com/fullstackio/books/build-a-spotify-connected-app/module_03/lesson_03.02/protected/src/client/package.json#L5 }
  "proxy": "http://localhost:8888",
```

Now, if we set up a request to our Express app's `/refresh_token` endpoint (without the `http://localhost:8888`) using [`fetch()`](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch) in our `App.js`, we should see some JSON data in addition to the tokens printed in our console.

```js { actualFilename=./protected/src/client/App.js endLine=21 startLine=6 statedFilename=client/src/App.js url=https&#x3A;//gitlab.com/fullstackio/books/build-a-spotify-connected-app/module_03/lesson_03.02/protected/src/client/App.js#L6 }
  useEffect(() => {
    const queryString = window.location.search;
    const urlParams = new URLSearchParams(queryString);
    const accessToken = urlParams.get('access_token');
    const refreshToken = urlParams.get('refresh_token');

    console.log(accessToken);
    console.log(refreshToken);

    if (refreshToken) {
      fetch(`/refresh_token?refresh_token=${refreshToken}`)
        .then(res => res.json())
        .then(data => console.log(data))
        .catch(err => console.error(err));
    }
  }, []);
```

## Running two servers at the same time

Another improvement we can make to our development workflow is adding a build tool to let us run multiple npm commands at the same time. To do this, we'll add an npm package called [Concurrently](https://www.npmjs.com/package/concurrently) to the root of our project.

Streamline development in a client/server architecture with Concurrently

Even when I use the code provided to you, my callback doesn't include the access token and refresh token, only the code and state, like this: http://localhost:3000/callback?code=XXX&state=XXX

SonjaBre

After adding the "proxy": "https://localhost:8888" section to the client package.json, I'm running into this error message:  Invalid options object. Dev Server has been initialized using an options object that does not match the API schema. - options.allowedHosts[0] should be a non-empty string.Has anyone run into this?

Learn

The newline Guide to Building Your First GraphQL Server with Node and TypeScript

Teach

Amelia Wattenberger

Author of Fullstack D3

Community

Build a Spotify Connected App

Module 1: Intro & Dev Environment Setup

Introduction:

Start Here

Introduction: (6:46)

Course Introduction

Lesson 1: (6:19)

How to Setup a React Developer Environment with nvm

Module 2: Getting Started with REST APIs & Express

Introduction: (1:04)

Module 1 Introduction

Lesson 1: (4:09)

What is an API?

Lesson 2: (9:38)

Okay, but what is a REST API?

Lesson 3: (3:57)

What is Express? The Basics of the Node.js web framework

Lesson 4: (5:27)

The Basics of Express Router - Requests and Responses

Module 3: Authentication & Authorization with Spotify

Introduction: (0:55)

Module 2 Introduction

Lesson 1: (3:16)

Getting Started with the Spotify Developer Dashboard

Lesson 2: (2:54)

Add nodemon to an Express App to Restart Node Automatically

Lesson 3: (8:56)

What is OAuth and How Does it Work? [with examples]

Lesson 4: (20:00)

How to Implement OAuth Flow in Express and Node.js

Module 4: Setting Up a React Front-End

Introduction: (0:57)

Module 3 Introduction

Lesson 1: (7:59)

How to Pass OAuth Tokens to a React App

Lesson 2: (6:32)

Optimize React and Express.js code with npm concurrently

Module 5: Login State & Front-End Scaffolding

Introduction: (1:18)

Module 4 Introduction

Lesson 1: (13:10)

Using Local Storage to Persist Login State

Lesson 2: (7:11)

How to Fetch Spotify API Data with Credentials with Axios

Lesson 3: (4:18)

How to Setup and Scaffold React Router

Lesson 4: (14:43)

Beginner's Guide to Styled Components in React [with examples]

Module 6: Building & Styling the UI

Introduction: (1:12)

Module 5 Introduction

Lesson 1: (2:03)

How to Build a Login Page in React

Lesson 2: (24:33)

How to Build a Profile Page in React with Spotify API Data

Lesson 3: (14:59)

How to Build a Spotify Top Artists & Top Tracks Page in React

Lesson 4: (11:11)

How to Build a Spotify Playlists Page in React

Lesson 5: (16:50)

How to Build a Spotify Individual Playlist Page in React

Lesson 6: (3:49)

How to Build a React Loading Animation Component

Module 7: Deploying to the Internet

Introduction: (0:39)

Module 6 Introduction

Lesson 1: (5:52)

How to Change Your React Favicon and Social Preview Images

Lesson 2: (12:36)

How to Deploy React to Heroku With a Node.js Server

Lesson 3: (1:43)

How to Add a README.md File to React

Module 8: Course Wrap Up

Lesson 1: (1:59)