INSTALLING WEBPACK
You need to have node.js installed.
$ npm install webpack -gThis makes the webpack command available.
SETUP THE COMPILATION
Start with a empty directory.
Create these files:
add entry.js
document.write("It works.");
add index.html
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<script type="text/javascript" src="bundle.js" charset="utf-8"></script>
</body>
</html>
Then run the following:
$ webpack ./entry.js bundle.js
It will compile your file and create a bundle file.
If successful it displays something like this:
Version: webpack 1.14.0
Time: 12ms
Asset Size Chunks Chunk Names
bundle.js 1.42 kB 0 [emitted] main
chunk {0} bundle.js (main) 28 bytes [rendered]
[0] ./tutorials/getting-started/setup-compilation/entry.js 28 bytes {0} [built]
Open
index.html in your browser. It should display It works.SECOND FILE
Next, we will move some code into an extra file.
add content.js
module.exports = "It works from content.js.";
update entry.js
- document.write("It works.");
+ document.write(require("./content.js"));
And recompile with:
$ webpack ./entry.js bundle.js
Update your browser window and you should see the text
webpack will analyze your entry file for dependencies to other files. These files (called modules) are included in your It works from content.js..bundle.js too. webpack will give each module a unique id and save all modules accessible by id in the bundle.js file. Only the entry module is executed on startup. A small runtime provides the require function and executes the dependencies when required.THE FIRST LOADER
We want to add a CSS file to our application.
webpack can only handle JavaScript natively, so we need the
css-loader to process CSS files. We also need the style-loader to apply the styles in the CSS file.
Run
npm install css-loader style-loader to install the loaders. (They need to be installed locally, without -g) This will create a node_modules folder for you, in which the loaders will live.
Let’s use them:
add style.css
body {
background: yellow;
}
update entry.js
+ require("!style!css!./style.css");
document.write(require("./content.js"));
Recompile and update your browser to see your application with yellow background.
By prefixing loaders to a module request, the module went through a loader pipeline. These loaders transform the file content in specific ways. After these transformations are applied, the result is a JavaScript module.BINDING LOADERS
We don’t want to write such long requires
require("!style!css!./style.css");.
We can bind file extensions to loaders so we just need to write:
require("./style.css")
update entry.js
- require("!style!css!./style.css");
+ require("./style.css");
document.write(require("./content.js"));
Run the compilation with:
webpack ./entry.js bundle.js --module-bind 'css=style!css'Some environments may require double quotes: –module-bind “css=style!css”
You should see the same result:
A CONFIG FILE
We want to move the config options into a config file:
add webpack.config.js
module.exports = {
entry: "./entry.js",
output: {
path: __dirname,
filename: "bundle.js"
},
module: {
loaders: [
{ test: /\.css$/, loader: "style!css" }
]
}
};
Now we can just run:
webpack
to compile:
Version: webpack 1.14.0
Time: 163ms
Asset Size Chunks Chunk Names
bundle.js 10.7 kB 0 [emitted] main
chunk {0} bundle.js (main) 8.85 kB [rendered]
[0] ./tutorials/getting-started/config-file/entry.js 64 bytes {0} [built]
[1] ./tutorials/getting-started/config-file/style.css 943 bytes {0} [built]
[2] ../~/css-loader!./tutorials/getting-started/config-file/style.css 197 bytes {0} [built]
[3] ../~/css-loader/lib/css-base.js 1.51 kB {0} [built]
[4] ../~/style-loader/addStyles.js 6.09 kB {0} [built]
[5] ./tutorials/getting-started/config-file/content.js 45 bytes {0} [built]The webpack command-line will try to load the filewebpack.config.jsin the current directory.
A PRETTIER OUTPUT
If the project grows the compilation may take a bit longer. So we want to display some kind of progress bar. And we want colors…
We can achieve this with
webpack --progress --colorsWATCH MODE
We don’t want to manually recompile after every change…
webpack --progress --colors --watch
Webpack can cache unchanged modules and output files between compilations.
When using watch mode, webpack installs file watchers to all files, which were used in the compilation process. If any change is detected, it’ll run the compilation again. When caching is enabled, webpack keeps each module in memory and will reuse it if it isn’t changed.
DEVELOPMENT SERVER
The development server is even better.
npm install webpack-dev-server -gwebpack-dev-server --progress --colors
This binds a small express server on localhost:8080 which serves your static assets as well as the bundle (compiled automatically). It automatically updates the browser page when a bundle is recompiled (SockJS). Open http://localhost:8080/webpack-dev-server/bundle in your browser.
The dev server uses webpack’s watch mode. It also prevents webpack from emitting the resulting files to disk. Instead it keeps and serves the resulting files from memory.
Main article is here: http://webpack.github.io/docs/tutorials/getting-started/
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