Getting started with Parcel.js

The major frontend frameworks(libraries) like Angular, React, Vuejs are pre-configured with a bundler( webpack ) which helps build and bundle your assets/files into a single file and served in the browser. When using vanilla javascript, you can also use a bundler to do same. This is where Parcel comes in, which is a fast, zero-configuration web application bundler.

Parcel.js prides itself has been all about developers experience, saving developers time to do small tasks. For instance, if your app is running a parcel-bundler in development, you don't need to kill your server to install a new package. Just import the package and Parcel will install it under the hood for you.

In this article, we will demonstrate how Parcel works with a simple project. To get started, ensure you have Node installed on your computer. Let's create a folder(parcel-demo) to house our project and in that folder, create two files index.html and index.js. Open the folder in your code editor(I use VsCode ).

index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Parcel Demo</title>
</head>
<body>
    <h1>This is a parcel demo</h1>
    <script src="index.js"></script>
</body>
</html>

Create a third file called demo.js and put the following code

demo.js
export function sayHello(name) {
    return `Hello ${name}`
}

Import this inside the index.js file as below

import { sayHello } from './demo';

sayHello('Dave');

Open the index.html file in the browser, check the console and you will see error,

Uncaught SyntaxError: Cannot use import statement outside a module

Recall that this es6 which is not understood by the browser. This is where Parcel.js comes; to transpile the es6 and bundle our app via the entry index.html file. Let's install parcel.js into our project.

Run yarn init -y or npm init -y in the root of your project to create the package.json file.

To add Parcel as a package to our project, run yarn add parcel-bundler --dev or npm install parcel-bundler --save-dev. This installs parcel as a dev dependency.

Open the package.json created and add

"scripts": {
    "dev": "parcel index.html",
    "build": "parcel build index.html"
  },

When you run yarn dev or npm run dev(visit http://localhost:1234/ to see the page), parcel bundles all our files and assets into a single file through the entry point of the app index.html. Also, the error above disappears as parcel allows you to use es6 import statement. To run in production mode, use yarn build or npm run build.

Conclusion

We can see that Parcel gives the bundling effect as webpack does. It also has zero-config unlike webpack and other bundlers. Other features Parcel provides include Code Splitting and Hot Module Replacement . For more details, visit the Parceljs documentation to explore further.

David's Blog

David's Blog

Getting started with Parcel.js

Conclusion