Write bundle to disk

[KyleAMathews]

I'm developing an app that has several entry points — one of which needs a custom html file that I'm generating using a View in my hapi.js server.

Is there a way I can configure the dev-server to write the generated js files to disk? Right now I either have to have another webpack watcher to compile files or stop and manually compile the files when I make a change to that particular part of the code.

[iirvine]

I'd like to see an option like this as well. At least from my initial webpack experiments, it seems that being able to write the dev server output to disk would make working in parallel with another server much simpler. Right now I have a fairly complicated work-around of loading static assets from the dev server based on an environment variable, which works okay for a single bundle but breaks code-splitting.

[sokra]

The webpack-dev-server doesn't write files to disk. You can use webpack --watch which writes files to disk. But why would you need to access the generated assets? This shouldn't be required.
When using with an existing server you should thread the webpack assets as blackbox that exists at a special URL.

[iirvine]

Right, it makes a bit more sense now that I've worked with webpack a little more - it just necessitates my server having some notion of that blackbox in development, rather than always just serving assets from disk.

[devel-pa]

yesterday, a bad day, so I'll delete the things I wrote here.
Webpack works with WebStorm very well.

You have to set in remote urls the mapping of your sources starting from "webpack:///."

PS: and it worked only for a minute. now, back to nothing

[sompylasar]

But why would you need to access the generated assets? This shouldn't be required.

While debugging the build process (webpack build configuration, webpack loaders configuration, project file structure), you could have to look into the generated files to understand what has gone wrong.

BTW, webpack-dev-server does not reload webpack config file when it changes either. So we have to restart the server. Luckily, the browser-side waits for it and catches up (thanks for that!).

[max-mykhailenko]

+1

[sokra]

Writing to disk is not an option for the webpack-dev-server. Instead you can use webpack --watch which does the same but writes files to disk + a static fileserver.

[diurnalist]

@sompylasar this is a very late reply, but you can examine the generated assets if you visit your dev server under the /webpack-dev-server path. I.e. if you're running it on 9000, http://localhost:9000/webpack-dev-server.

[sompylasar]

@diurnalist Sure, I know. This is how I do debugging in the browser. But I wanted to have the files in my text editor rather than in the browser's developer tools.

[KyleAMathews]

@sokra but that means you can't do hot-reloads...

[diurnalist]

@KyleAMathews how so? Nothing about hot reloads requires the assets be written to disk. I'm using it in a project right now without issue.

[KyleAMathews]

@diurnalist sorry wasn't clear — I want assets written to the disk. I was the one who originally created this issue ;-)

Right now I have to run both webpack-dev-server and webpack -w.

[diurnalist]

@KyleAMathews hmm, I'm still trying to understand why you need to run two webpack compilations. It seems irrelevant how the bundle is served. The only thing I can think is that somehow you need to do additional processing outside of webpack land on one of your output files? Feel free to send me an email (listed on my profile) - I've had to deal with a few weird things when integrating webpack into a big project, maybe my experience can be of use.

[max-mykhailenko]

@KyleAMathews you can try setup git hook and run webpack on commit, pull etc.

[KyleAMathews]

@diurnalist I have two entry points, one of which I want served by webpack-dev-server for hot reloading (an admin page) and the other entry point I need compiled to disk so it can be loaded as part of a server generated React page.

@max-mykhailenko I need to see the results of my changes before committing ;-)

[sokra]

I have two entry points

You should have two configurations, because the target option differs: web and node.

[KyleAMathews]

@sokra I was a bit unclear — the target for both entry points is the web — React is used to generate the initial html page that's sent but I still need the compiled js to animate the react app in the browser.

[diurnalist]

@KyleAMathews so, just to be clear (again, happy to discuss via email, these GH comment reply flows get a bit ridic after a certain point...) - does your generated HTML file need to include the script inlined? Or is it fine to include it as an external link? Obviously if the latter is true, you can simply link your script in:

<script src="http://localhost:9090/js/your-react-bundle.js"></script>

You'd just need to be able to change the host for when you deploy the app to a remote server, obviously.

If you need to actually inline your script... that's a different issue. But, I'd ask: why would you need to do that? For what it's worth, it's possible. I'm currently doing it to bootstrap some page-specific JSON into my app when it starts. The tricky part here is you need to understand what IDs webpack has assigned your modules. To do that, you need to parse the stats object webpack returns when a compilation completes. I have some code I could open-source that helps with this.

Basically, I have some script template that looks something like this:

webpackJsonp([], {
  0: function (module, exports, require) {
    var App = require(__APPLICATION_MODULE_ID__);
    App.start(__BOOTSTRAP_DATA__);
  }
});

And then when I'm generating my HTML page, I just read that template and replace the tokens with the webpack module id for the App module and the JSON string of bootstrap data. This works essentially by injecting a dummy webpack chunk on to the page that has no dependencies. You would need to ensure that you have loaded the main webpack library on the page before doing this, or else the webpackJsonp function will not exist yet.

[quantuminformation]

I basically want the server auto refreshing when I make changes in the code, similar to how the ember-cli works.

[nickpresta]

I've tried to follow allow this thread and the linked threads, but I'm still unsure of my current options.

It is possible to run Webpack Dev Server in "hot reload" mode (to support React Hot Loader, etc) while still writing the files to disk?

[JorritPosthuma]

I'd like to add an argument for adding this option 😊. When using electron, in certain cases, you are only allowed to use files from a file: path: https://github.com/atom/electron/blob/master/atom/renderer/lib/web-view/web-view-attributes.coffee#L201

@nickpresta As far as I know, not right now. You have to run a separate webpack -w.

[thelinuxlich]

+1 for dev server writing to disk!

[sheerun]

We also needed it for node's native modules (.node). They can't be loaded from web server.

[mrberggg]

+1 for writing to disk. Just adds confusion when starting out.

[gajus]

The core features are dictated by the mainstream use. This isn't a mainstream use case. Plugins are to support alternative use cases.

[ashish-chopra]

Thanks @gajus. After a long search related to emit usecase i landed upto this thread and found your plugin a Savior. THanks. +1 for your plugin.

[cchamberlain]

I am writing a C# => TypeScript transpiler plugin. TypeScript editors / type checkers require hard files on disk. Currently detecting if I'm running in watch and using fs.writeFile to emit assets, otherwise I use the assets object. It would be nice to be able to route assets to avoid less differences in dev / prod code paths.

[SteveGBanton]

@anuja8275 @simon-paris @ashish-chopra What if you just use:

"start": "./node_modules/.bin/webpack-dev-server && ./node_modules/.bin/webpack"

in your package.json? Dev server runs first and you make your edits. When done you ctrl-c to close the terminal process and webpack will automatically start to create the file system bundle.

[Kos]

@SteveGBanton I don't think that would provide good usability - most users expect Ctrl+C to be instantenous and a webpack run can easily take half a minute.

[feusebio]

I had some problems to get file bundled in dir that i want, the problem was because i run webpack in Windows, and i had to change the slash in paths.
Ex: context: __dirname + '/resources/assets/js', to context: __dirname + '\\resources\\assets\\js',

[SteveGBanton]

@Kos You're right, might be a bit awkward in some cases. This also works for me:

"scripts": {
"start": "./node_modules/.bin/webpack-dev-server",
"start-disk": "./node_modules/.bin/webpack --watch"
}

Run 'npm start' first, then 'npm run start-disk' in a separate terminal window. You can develop with webpack-dev-server and bundle is automatically written to disk at the same time through webpack --watch... Might need to delete your bundle file to start.

[asumaran]

I've spent 20 minutes reloading and deleting node_modules and reinstalling everything just to find out webpack-dev-server doesn't write to disk. Usually I want to check what in the bundle is changing or sometimes I want to check how the code is generated (for technical purposes) That's why I think it's useful to have an option to write the generated files to disk so I can check them in my own editor to inspect changes.

[herzinger]

@gajus great plugin, thanks!

That being said, I'm also of the opinion it should be integrated in the core project, as an optional flag. I don't even have a complicated user case, I just like to see what's being outputted right there in my ide whenever I want to. I don't believe I'm alone in that.

[atrauzzi]

Working on an electron app. Would like to be able to serve the initial main from the filesystem, but have subsequent loads work via the server.

[veetil09]

@gajus Hey, thanks for the plugin. You may want to surround the fs.writeFileSync(relativeOutputPath.split('?')[0], assetSource); in a try-catch since it can throw an exception.

[gajus]

@gajus Hey, thanks for the plugin. You may want to surround the fs.writeFileSync(relativeOutputPath.split('?')[0], assetSource); in a try-catch since it can throw an exception.

PR welcome.

[veetil09]

gajus/write-file-webpack-plugin#47

…

On Tue, Sep 26, 2017 at 4:46 AM, Gajus Kuizinas ***@***.***> wrote: @gajus <https://github.com/gajus> Hey, thanks for the plugin. You may want to surround the fs.writeFileSync(relativeOutputPath.split('?')[0], assetSource); in a try-catch since it can throw an exception. PR welcome. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#62 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AFxjB8FxSj9fYXuYCUkmRSlKir5wqHtPks5smLnXgaJpZM4Cl6x8> .

[valorloff]

This feature is highly needed for HMR universal apps, when need re-bundle server and send changed client.bundle to the client

[heisian]

@everyone I see at least two viable solutions provided here in this thread so let's make a couple things clear before we keep asking to add more stuff:

1. ANY addition to webpack functionality is by nature a plugin. So if you think writing to disk should be an option and not a plugin, guess what, any way you slice it it will be a (internal) plugin.
2. @gajus 's solution which I'm about to try out! https://github.com/gajus/write-file-webpack-plugin
3. @chikara-chan 's super easy plugin which I will try first.

Now, the reason I want write-to-disk is b/c I need to be able to make server-side changes without having to re-compile the client from scratch when the server restarts. I am aware of chokidar watching for require.cache deletion, but it didn't work at all in my case.

I've separated out the processes, but the only way I see the forked server process being able to get the references to the webpack assets in-memory is via node's IPC channels (someone correct me if I'm wrong!).

While probably the best/correct solution, I don't really want to mess with it when serving static files on disk is trivial in comparison. Being able to use HMR w/ that absolute path on-disk would be so easy I could eat an everything bagel with morning coffee, take a dump, and read the paper while still filling my daily quota of code lines. Let's see if this works...

[heisian]

Alright the above doesn't really work because webpack-hot-client does us the gracious service of updating browser assets via websocket and I was trying to cut that part out completely.

So! I still need a mechanism to have the server server and the client server as separate processes... more easily done by simply having two servers on two different ports.. pretty much negating the need to write anything to disk in dev. ciao

[paulomunoz]

@sokra:

But why would you need to access the generated assets? This shouldn't be required.

I would normally agree with you, but at this moment I am trying to use Visual Studio Code debugging tools to debug my app, and it only works if you provide it with the file location in disk. I used https://github.com/gajus/write-file-webpack-plugin to do the trick, and that worked fine.

Normally I would not want it to be written in the disk though, so I'll see if I can separate this in a different npm script or something like that!

[Matchlighter]

Just my two cents: My project's backend is written in Python using Django. The Webpack HTTP Plugin just wouldn't cut it for my multiple-entry application, so I wrote a plugin to make Webpack write a file with all of the chunks it output and all of their required chunks. Django could then read that file and add the appropriate HTML tags. That blows up when Webpack doesn't spit out any files.
I will admit that the use case are few, but they do exist. @gajus plugin worked dandily. At least an official link in the README would be nice.

[euclid1990]

I have released a plugin that solved this problem

https://github.com/euclid1990/write-assets-webpack-plugin

[TacB0sS]

Extremely late for the party, but my 2 cents on this:

You are correct that when you are busy in developing your page and components and styles and apis, this is somewhat redundant, but when you are configuring your environment, adding third party sdks, scripts, configurations, files (and god know what other requirements they have) all that while maintaining dev and prod (maybe also staging) configurations.. things gets complicated, and although I can just execute webpack instead of webpack-dev-server and see the results, I do prefer to catch as many bird in one run...

And since you refuse adding a flag to do it.. you force us, and I do believe most of us, to just use a plugin even if just to save us few seconds every time.. cause these few second pile up eventually, and personally I hate wasting my time for no god reason.

[chrisisler]

Just wanted to chime in to say again what has already been said: Django + webpack --watch is annoying without the awesomeness of hot reloading. Haven't tried @gajus plugin. This should be a core feature, or at least mentioned somewhere in the webpack-dev-server documentation.

[trusktr]

But why would you need to access the generated assets?

Because I'm developing a library which I need to test in a browser, but I also need to import it from the file system in Node.js applications (f.e. other Electron apps that I'm also testing).

[trusktr]

Essentially webpack-dev-server is designed to be used while developing apps, not while developing libraries.

[damianobarbati]

Facing same issue. @sokra @trusktr in my scenario I'm trying to write a library and in the meantime watch it in an app:

const pkg = require('./package.json');
const webpack = require('webpack');
const path = require('path');

module.exports = [{
    entry: './src/index.js',
    output: {
        path: path.resolve(__dirname, './dist'),
        filename: 'dist.min.js',
        library: pkg.name,
        libraryTarget: 'umd'
    },
    watch: true,
    module: {
        rules: [{
            test: /\.(js|jsx)$/,
            exclude: /node_modules/,
            use: [{
                loader: 'babel-loader',
                options: {
                    cacheDirectory: true,
                },
            }],
        }],
    },
    externals: {
    },
},{
    entry: './demo/index.js',
    output: {
        publicPath: '/',
        path: __dirname + '/demo',
        filename: 'bundle.js'
    },
    module: {
        rules: [{
            test: /\.(js|jsx)$/,
            exclude: /node_modules/,
            use: [{
                loader: 'babel-loader',
                options: {
                    cacheDirectory: true,
                },
            }],
        }],
    },
    resolve: {
        alias: {
            Form: path.resolve(__dirname, './dist/dist.min.js'),
        },
    },
    plugins: [
        new webpack.HotModuleReplacementPlugin(),
    ],
    devServer: {
        contentBase: './demo',
        hot: true
    },
}];

The latter does not find the "resolved" => "Form" bundle on disk because it is not written.
If I trigger separated the build, subsequent changes to form bundle do not trigger dev-server "watch".

:(

[smac89]

In webpack config:

{
   ...
    devServer: { // https://webpack.js.org/configuration/dev-server/#devserverwritetodisk-
        writeToDisk: true,
    },
}

[Mr-Lion]

In webpack config:

{
   ...
    devServer: { // https://webpack.js.org/configuration/dev-server/#devserverwritetodisk-
        writeToDisk: true,
    },
}

Hello friends,

I've been dealing with the problem for several weeks and look in vain for a sensible solution.

The one with the "writeToDisk: true" definitely doesn't work.
No matter what I did and how I tried every possible start, I could not write the "css" for the style on the disc.

Furthermore, the webpack-dev-server does not work at all with a multi-config. Here comes the mistake:

I don't understand why the "CSS" files are written into the memory. The developer must have really burned his brain. If you search the internet for this problem, you will find millions of complaints where people are looking for a solution. One should make the decision easy for a user.

Oh yes, why only "index.html" works here and not, for example: "index.php" is also questionable.

I urgently ask for help!
I thank you in advance.