How to prevent moment.js from loading locales with webpack?

Hello is there anyway you can stop moment.js from loading all the locales(I just need english) when your using webpack? I'm looking at the source it seems that if hasModule is defined which it is for webpack then it always tries to require() every locale. I'm pretty sure this needs pull request to fix. But is there anyway we can fix this with a webpack config.

Here is my webpack config to load momentjs

resolve: {
            alias: {
                moment: path.join(__dirname, "src/lib/bower/moment/moment.js")

Then anywhere I need it I just do require('moment') this works but its adding about 250kb of unneeded language files to my bundle. Also I'm using the bower version of momentjs and gulp.

Also if this can't be fixed by a webpack config here is a link to the function where it loads the locales I tried adding "&& module.exports.loadLocales" to the if statement but I guesse webpack doesnt acaully work in a way where that would work it just requires no matter what I think it uses a regex now so I don't really know how you would even go about fixing it. Anyways thanks for any help.



The code require('./locale/' + name) can use every file in the locale dir. So webpack includes every file as module in your bundle. It cannot know which language you are using.

There are two plugins that are useful to give webpack more information about which module should be included in your bundle: ContextReplacementPlugin and IgnorePlugin.

require('./locale/' + name) is called a context (a require which contains an expression). webpack infers some information from this code fragment: A directory and a regular expression. Here: directory = ".../moment/locale" regular expression = /^.*$/. So by default every file in the locale directory is included.

The ContextReplacementPlugin allows to override the inferred information i.e. provide a new regular expression (to choose the languages you want to include).

Another approach is to ignore the require with the IgnorePlugin.

Here is an example:

var webpack = require("webpack");
module.exports = {
  // ...
  plugins: [
    new webpack.ContextReplacementPlugin(/moment[\/\\]locale$/, /de|fr|hu/)
    // new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/)

In our project, I include moment like this: import moment from 'moment/src/moment'; and that seems to do the trick. Our usage of moment is very simple though, so I'm not sure if there will be any inconsistencies with the SDK. I think this works because WebPack doesn't know how to find the locale files statically, so you get a warning (that's easy to hide by adding an empty folder at moment/src/lib/locale/locale) but no locale includes.


Based on Adam McCrmick's answer, you were close, change your alias to:

resolve: {
    alias: {
        moment: 'moment/src/moment'

With webpack2 and recent versions of moment you can do:

import {fn as moment} from 'moment'

And then in webpack.config.js you do:

resolve: {
    packageMains: ['jsnext:main', 'main']

The proper modular moment library will come up with Version 3 at some point so currently as I am using angular-cli without --eject I just ended up of using like import * as moment from 'moment-mini';


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