Home >Web Front-end >JS Tutorial >Detailed explanation of the steps to use dev-server in webpack

Detailed explanation of the steps to use dev-server in webpack

php中世界最好的语言Original: 2018-05-02 14:24:541968browse

This time I will bring you a detailed explanation of the steps for using dev-server in webpack. What are the precautions for using dev-server in webpack? Here are practical cases, let’s take a look.

webpack-dev-server

webpack-dev-server is a small Node.js Express server that uses webpack-dev-middleware to serve webpack package, in addition to this, it also has a micro runtime that connects to the server through Sock.js.

Let’s take a look at the followingconfig file(webpack.config.js )

var path = require("path");
module.exports = {
 entry:{
 app:["./app/main.js"]
 },
 output:{
 path:path.resolve(dirname,"build"),
 publicPath:"/assets/",
 filename:"bundle.js"
}
}

Here you put your source files under the app folder and package them into bundle.js under the build folder through webpack.

Note: webpack-dev -server is an independent NPM package, you can install it through npm install webpack-dev-server.

Basic directory

webpack-dev-server will be installed by default Use the current directory as the base directory, unless you specify it.

webpack-dev-server --content-base build/

The above command is executed in the command line, which will use the build directory as the root directory. One thing to note is: webpack-dev-server generates The package is not placed in your real directory, but in the memory.

We create a new index.html file in the basic directory, and then enter http://localhost in the browser: 8080 access.

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>Document</title>
</head>
<body>
 <script src="assets/bundle.js"></script>
</body>
</html>

Automatic refresh

webpack-dev-server supports two modes to automatically refresh the page.

iframe mode (the page is placed in an iframe and reloaded when changes occur)
inline mode (add the client entry of webpack-dev-sever to the bundle)

Both modes support Hot Module Replacement. The advantage of hot module replacement is that only the updated part is replaced instead of page reloading.

iframe Mode
No additional configuration is required to use this mode, you only need to access it in the following URL format

http://«host»:«port»/webpack-dev-server/« path»

For example: http://localhost:8080/webpack-dev-server/index.html.

inline mode

inline mode The URL we visit does not need to change. There are two situations when enabling this mode:

1 When starting webpack-dev-server from the command line, two things need to be done:

Add the --inline command to the command line
Add devServer:{inline:true} to webpack.config.js

2 When starting webpack-dev-server with Node.js API, we also need to do two things:

Since there is no inline option in the configuration of webpack-dev-server, we You need to add webpack-dev-server/client?http://«path»:«port»/ to the entry entry point of the webpack configuration.
Change Add to the html file

 var config = require("./webpack.config.js");
 var webpack = require('webpack');
 var WebpackDevServer = require('webpack-dev-server');
config.entry.app.unshift("webpack-dev-server/client?http://localhost:8080/");
var compiler = webpack(config);
var server = new WebpackDevServer(compiler, {
 contentBase:'build/',
 publicPath: "/assets/"
});
server.listen(8080);

Run the above code in Node .

Note: The devSever configuration item in the webpack configuration is only valid in command line mode.

(Hot Module Replacement) Hot module replacement

Run inline mode in the command line and enable hot module replacement

Just add more here The --hot command is OK. As shown below.

webpack-dev-server --content-base build --inline --hot

Note: In command line mode, output.publicPath must be configured in webpack.config.js to specify the access location of the compiled package (bundle) .

Run inline mode in Nodejs API and enable hot module replacement

You need to do the following three things here:

In webpack.config. Add to the entry option of js: webpack/hot/dev-server
Add to the plugins option of webpack.config.js: new webpack.HotModuleReplacementPlugin()
Add in the configuration of webpack-dev-server: hot:true

Configuration options in webpack-dev-server

var WebpackDevServer = require("webpack-dev-server");
var webpack = require("webpack");
var compiler = webpack({
 // configuration
});
var server = new WebpackDevServer(compiler, {
 // webpack-dev-server options
 contentBase: "/path/to/directory",
 // Can also be an array, or: contentBase: "http://localhost/",
 hot: true,
 // Enable special support for Hot Module Replacement
 // Page is no longer updated, but a "webpackHotUpdate" message is send to the content
 // Use "webpack/hot/dev-server" as additional module in your entry point
 // Note: this does _not_ add the `HotModuleReplacementPlugin` like the CLI option does. 
 // Set this as true if you want to access dev server from arbitrary url.
 // This is handy if you are using a html5 router.
 historyApiFallback: false,
 // Set this if you want to enable gzip compression for assets
 compress: true,
 // Set this if you want webpack-dev-server to delegate a single path to an arbitrary server.
 // Use "**" to proxy all paths to the specified server.
 // This is useful if you want to get rid of 'http://localhost:8080/' in script[src],
 // and has many other use cases (see https://github.com/webpack/webpack-dev-server/pull/127 ).
 proxy: {
 "**": "http://localhost:9090"
 },
 setup: function(app) {
 // Here you can access the Express app object and add your own custom middleware to it.
 // For example, to define custom handlers for some paths:
 // app.get('/some/path', function(req, res) {
 // res.json({ custom: 'response' });
 // });
 },
 // pass [static options](http://expressjs.com/en/4x/api.html#express.static) to inner express server
 staticOptions: {
 },
 // webpack-dev-middleware options
 quiet: false,
 noInfo: false,
 lazy: true,
 filename: "bundle.js",
 watchOptions: {
 aggregateTimeout: 300,
 poll: 1000
 },
 // It's a required option.
 publicPath: "/assets/",
 headers: { "X-Custom-Header": "yes" },
 stats: { colors: true }
});
server.listen(8080, "localhost", function() {});
// server.close();

Believe it or not After reading the case in this article, you have mastered the method. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Detailed explanation of the steps to use dev-server in webpack

Related articles