A Beginner's Guide to Setup React.js Environment Using Npm, Babel 6 and Webpack
Facebook has really changed the way we think about front-end UI development with the introduction of React. One of the main advantages of this component based approach is, it is easy to reason about as the view is just a function of props and state.
In fact, these tools are not required to use React and but in order to get the most out of the features of ES6, JSX and bundling, we need them. In this blog post we are going to see how to setup a React development environment without being sidetracked by the tools.
A Disclaimer: The approach that I am going to share is just for beginners to understand on how to get started with React as going by this lean way has helped a lot when I started learning React.
Let’s start from scratch
Create a new folder ‘react-hello-world’ and initialize it with npm.
1 2 3
Accept the default for all the prompts
Installing and Configuring Webpack
Webpack is a module bundler which takes modules with dependencies and generates static assets by bundling them together based on some configuration.
The support of loaders in Webpack makes it a perfect fit for using it along with React and we will discuss it later in this post with more details.
Let’s start with installing webpack using npm
Webpack requires some configuration settings to carry out its work and the best practice is doing it via a config file called webpack.config.js.
Update the config file as follows
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
The minimalist requirement of a Webpack config file is the presence of entry and output properties.
APP_DIR holds the directory path of the React application’s codebase and the
BUILD_DIR represents the directory path of the bundle file output.
As the name suggests entry specifies the entry file using which the bundling process starts. If you are coming from C# or Java, it’s similar to the class that contains main method. Webpack supports multiple entry points too. Here the index.jsx in the src/client/app directory is the starting point of the application
The output instructs Webpack what to do after the bundling process has been completed. Here, we are instructing it to use the src/client/public directory to output the bundled file with the name bundle.js
Let’s create the index.jsx file in the ./src/client/app and add the following code to verify this configuration.
Now in the terminal run the following command
The above command runs the webpack in the development mode and generates the bundle.js file and its associated map file bundle.js.map in the src/client/public directory.
To make it more interactive, create an index.html file in the src/client directory and modify it to use this bundle.js file
1 2 3 4 5 6 7 8 9 10
Now if you open the browser, you can see the Hello World! in the console log.
Note: There is a webpack loader called html-loader which automatically creates this html file with the correct location of bundle.js.
Setting Up Babel-Loader
As we have seen in the beginning, by using JSX and ES6 we can be more productive while working with React. But the JSX syntax and ES6, are not supported in all the browsers.
Hence, if we are using them in the React code, we need to use a tool which translates them to the format that has been supported by the browsers. It’s where babel comes into the picture.
While installing Webpack we touched a little on loaders. Webpack uses loaders to translate the file before bundling them
To setup install the following npm packages
The babel-preset-es2015 and babel-preset-react are plugins being used by the babel-loader to translate ES6 and JSX syntax respectively.
As we did for Webpack, babel-loader also requires some configuration. Here we need to tell it to use the ES6 and JSX plugins.
Create a .babelrc file and update it as below
1 2 3
The next step is telling Webpack to use the babel-loader while bundling the files
open webpack.config.js file and update it as below
1 2 3 4 5 6 7 8 9 10 11 12 13
The loaders property takes array of loaders, here we are just using babel-loader. Each loader property should specify what are the file extension it has to process via the test property. Here we have configured it to process both .js and .jsx files using the regular expression. The include property specifies what is the directory to be used to look for these file extensions. The loader property represents the name of the loader.
Now we all the setup done. Let’s write some code in React.
Use npm to install react and react-dom
Replace the existing console.log statement in the index.jsx with the following content
1 2 3 4 5 6 7 8 9 10
Then run the following command to update the bundle file with the new changes
Now, if you open the index.html in the browser you can see Hello React
Adding Some Complexity
Making Webpack to watch the changes
Running the webpack command on every time when you change the file is not a productive work. We can easily change this behavior by using the following command
Now Webpack is running in the watch mode, which will automatically bundle the file whenever there is a change detected. To test it, change Hello React to something else and refresh the index.html in the browser. You can see your new changes.
If you don’t like refreshing the browser to see the changes you can use react-hot-loader!
Using npm as a tool runner
./node_modules/.bin/webpack can be made even simpler by leveraging npm.
Update the packages.json as below
1 2 3 4 5 6 7 8
Now the command
npm run build runs Webpack in production mode, which minimizes the bundle file automatically and
npm run dev runs the Webpack in the watch mode.
Adding some files
In the sample we have seen only one Component called App. Let’s add some more to test the bundling setup.
Create a new file AwesomeComponent.jsx and update it as below
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
Then include it in the index.jsx file
1 2 3 4 5 6 7 8 9 10 11 12 13 14
If your Webpack is already running in watch mode then refresh the browser to see the AwesomeComponent in action!
In this blog post we have seen a lean approach for setting up a development environment to work with React. In the next blog post we will be extending this example to implement the flux architecture using Alt. You can get the source code associated with this blog post can be found in my github repository.