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Using webpack-dev-server and HMR

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Using webpack-dev-server and HMR

While developing, instead of using yarn encore dev --watch, you can use the webpack-dev-server:

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$ yarn encore dev-server

This serves the built assets from a new server at http://localhost:8080 (it does not actually write any files to disk). This means your script and link tags need to change to point to this.

If you’re using the encore_entry_script_tags() and encore_entry_link_tags() Twig shortcuts (or are processing your assets through entrypoints.json in some other way), you’re done: the paths in your templates will automatically point to the dev server.

Enabling HTTPS using the Symfony Web Server

If you’re using the Symfony web server locally with HTTPS, you’ll need to also tell the dev-server to use HTTPS. To do this, you can reuse the Symfony web server SSL certificate:

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# Unix-based systems
$ yarn dev-server --https --pfx=$HOME/.symfony/certs/default.p12

# Windows
$ encore dev-server --https --pfx=%UserProfile%\.symfony\certs\default.p12

dev-server Options

The dev-server command supports all the options defined by webpack-dev-server. You can set these options via command line options:

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$ yarn encore dev-server --https --port 9000

You can also set these options using the Encore.configureDevServerOptions() method in your webpack.config.js file:

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// webpack.config.js
// ...

Encore
    // ...

    .configureDevServerOptions(options => {
        options.https = {
            key: '/path/to/server.key',
            cert: '/path/to/server.crt',
        }
    })
;

New in version 0.28.4: The Encore.configureDevServerOptions() method was introduced in Encore 0.28.4.

Hot Module Replacement HMR

Encore does support HMR for Vue.js, but does not work for styles anywhere at this time. To activate it, pass the --hot option:

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$ ./node_modules/.bin/encore dev-server --hot

If you want to use SSL with self-signed certificates, add the --https, --pfx=, and --allowed-hosts options to the dev-server command in the package.json file:

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{
    ...
    "scripts": {
-        "dev-server": "encore dev-server",
+        "dev-server": "encore dev-server --https --pfx=$HOME/.symfony/certs/default.p12 --allowed-hosts=mydomain.wip",
        ...
    }
}

If you experience issues related to CORS (Cross Origin Resource Sharing), add the --disable-host-check and --port options to the dev-server command in the package.json file:

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{
    ...
    "scripts": {
-        "dev-server": "encore dev-server",
+        "dev-server": "encore dev-server --port 8080 --disable-host-check",
        ...
    }
}

Caution

Beware that it’s not recommended to disable host checking in general, but here it’s required to solve the CORS issue.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.