Bootstrap & Parcel

了解在你的含Bootstrap项目中如何使用Parcel。

On this page

Want to skip to the end? Download the source code and working demo for this guide from the twbs/examples repository. You can also open the example in StackBlitz but not run it because Parcel isn’t currently supported there.

Setup

We’re building a Parcel project with Bootstrap from scratch, so there are some prerequisites and upfront steps before we can really get started. This guide requires you to have Node.js installed and some familiarity with the terminal.

Create a project folder and set up npm. We’ll create the my-project folder and initialize npm with the -y argument to avoid it asking us all the interactive questions.
```
mkdir my-project && cd my-project
npm init -y
```
Install Parcel. Unlike our Webpack guide, there’s only a single build tool dependency here. Parcel will automatically install language transformers (like Sass) as it detects them. We use --save-dev to signal that this dependency is only for development use and not for production.
```
npm i --save-dev parcel
```
Install Bootstrap. Now we can install Bootstrap. We’ll also install Popper since our dropdowns, popovers, and tooltips depend on it for their positioning. If you don’t plan on using those components, you can omit Popper here.
```
npm i --save bootstrap @popperjs/core
```

Now that we have all the necessary dependencies installed, we can get to work creating the project files and importing Bootstrap.

Project structure

We’ve already created the my-project folder and initialized npm. Now we’ll also create our src folder, stylesheet, and JavaScript file to round out the project structure. Run the following from my-project, or manually create the folder and file structure shown below.

mkdir {src,src/js,src/scss}
touch src/index.html src/js/main.js src/scss/styles.scss

When you’re done, your complete project should look like this:

my-project/
├── src/
│   ├── js/
│   │   └── main.js
│   ├── scss/
│   │   └── styles.scss
│   └── index.html
├── package-lock.json
└── package.json

At this point, everything is in the right place, but Parcel needs an HTML page and npm script to start our server.

Configure Parcel

With dependencies installed and our project folder ready for us to start coding, we can now configure Parcel and run our project locally. Parcel itself requires no configuration file by design, but we do need an npm script and an HTML file to start our server.

Fill in the src/index.html file. Parcel needs a page to render, so we use our index.html page to set up some basic HTML, including our CSS and JavaScript files.

<!doctype html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Bootstrap w/ Parcel</title>
    <link rel="stylesheet" href="scss/styles.scss">
    <script type="module" src="js/main.js"></script>
  </head>
  <body>
    <div class="container py-4 px-3 mx-auto">
      <h1>Hello, Bootstrap and Parcel!</h1>
      <button class="btn btn-primary">Primary button</button>
    </div>
  </body>
</html>

We’re including a little bit of Bootstrap styling here with the div class="container" and <button> so that we see when Bootstrap’s CSS is loaded by Parcel.

Parcel will automatically detect we’re using Sass and install the Sass Parcel plugin to support it. However, if you wish, you can also manually run npm i --save-dev @parcel/transformer-sass.

Add the Parcel npm scripts. Open the package.json and add the following start script to the scripts object. We’ll use this script to start our Parcel development server and render the HTML file we created after it’s compiled into the dist directory.
```
{
   // ...
   "scripts": {
     "start": "parcel serve src/index.html --public-url / --dist-dir dist",
     "test": "echo \"Error: no test specified\" && exit 1"
   },
   // ...
}
```
And finally, we can start Parcel. From the my-project folder in your terminal, run that newly added npm script:
```
npm start
```

In the next and final section to this guide, we’ll import all of Bootstrap’s CSS and JavaScript.

Import Bootstrap

Importing Bootstrap into Parcel requires two imports, one into our styles.scss and one into our main.js.

Import Bootstrap’s CSS. Add the following to src/scss/styles.scss to import all of Bootstrap’s source Sass.
```
// Import all of Bootstrap's CSS
@import "bootstrap/scss/bootstrap";
```
You can also import our stylesheets individually if you want. Read our Sass import docs for details.
Import Bootstrap’s JS. Add the following to src/js/main.js to import all of Bootstrap’s JS. Popper will be imported automatically through Bootstrap.
```
// Import all of Bootstrap's JS
import * as bootstrap from 'bootstrap'
```
You can also import JavaScript plugins individually as needed to keep bundle sizes down:
```
import Alert from 'bootstrap/js/dist/alert'

// or, specify which plugins you need:
import { Tooltip, Toast, Popover } from 'bootstrap'
```
Read our JavaScript docs for more information on how to use Bootstrap’s plugins.
And you’re done! 🎉 With Bootstrap’s source Sass and JS fully loaded, your local development server should now look like this:

Now you can start adding any Bootstrap components you want to use. Be sure to check out the complete Parcel example project for how to include additional custom Sass and optimize your build by importing only the parts of Bootstrap’s CSS and JS that you need.

See something wrong or out of date here? Please open an issue on GitHub. Need help troubleshooting? Search or start a discussion on GitHub.