The build system uses Webpack to create your website/app. Don’t worry if you aren’t acquainted with Webpack. Out of the box, you won’t need to configure it because it already has everything set up.

Usage with quasar.config file

For cases where you need to tweak the default Webpack config you can do so by editing the /quasar.config file and configuring build > extendWebpack (cfg) method or build > chainWebpack (chain).

Example of adding ESLint loader to Webpack (assuming you’ve installed it):

build: {
  extendWebpack (cfg, { isServer, isClient }) {
    cfg.module.rules.push({
      enforce: 'pre',
      test: /\.(js|vue)$/,
      loader: 'eslint-loader',
      exclude: /(node_modules|quasar)/
    })
  }
}

Notice that you don’t need to return anything. The parameter of extendWebpack(cfg) is the Webpack configuration Object generated by Quasar for you. You can add/remove/replace anything from it, assuming you really know what you are doing.

Equivalent quasar.conf for chainWebpack():

build: {
  chainWebpack (chain, { isServer, isClient }) {
    chain.module.rule('eslint')
      .test(/\.(js|vue)$/)
      .enforce('pre')
      .exclude
        .add((/[\\/]node_modules[\\/]/))
        .end()
      .use('eslint-loader')
        .loader('eslint-loader')
  }
}

Inspecting Webpack Config

Quasar CLI offers a useful command for this:

$ quasar inspect -h

  Description
    Inspect Quasar generated Webpack/Esbuild config

  Usage
    $ quasar inspect
    $ quasar inspect -c build
    $ quasar inspect -m electron -p 'build.outDir'

  Options
    --cmd, -c        Quasar command [dev|build] (default: dev)
    --mode, -m       App mode [spa|ssr|pwa|bex|cordova|capacitor|electron] (default: spa)
    --depth, -d      Number of levels deep (default: 2)
    --path, -p       Path of config in dot notation
                        Examples:
                          -p module.rules
                          -p plugins
    --thread, -t     Display only one specific app mode config thread
    --help, -h       Displays this message

Webpack Aliases

Quasar comes with a bunch of useful Webpack aliases preconfigured. You can use them anywhere in your project and webpack will resolve the correct path.

Also if you configure to build with the Vue compiler version (quasar.config file > build > vueCompiler: true), vue$ resolves to vue/dist/vue.esm.js.

Adding Webpack aliases

To add your own alias you can extend the webpack config and merge it with the existing alias. Always use absolute paths.

import { defineConfig } from '#q-app/wrappers'
import { fileURLToPath } from 'node:url'

export default defineConfig((ctx) => {
  return {
    build: {
      extendWebpack (cfg, { isServer, isClient }) {
        cfg.resolve.alias = {
          ...cfg.resolve.alias, // This adds the existing alias

          // Add your own alias like this
          myalias: fileURLToPath(new URL('./src/somefolder', import.meta.url)),
        }
      }
    }
  }
})

Equivalent with chainWebpack():

import { defineConfig } from '#q-app/wrappers'
import { fileURLToPath } from 'node:url'

export default defineConfig((ctx) => {
  return {
    build: {
      chainWebpack (chain, { isServer, isClient }) {
        chain.resolve.alias
          .set('myalias', fileURLToPath(new URL('./src/somefolder', import.meta.url)))
      }
    }
  }
})

Webpack v5 compatibility issues

Quasar App CLI is using Webpack v5. If you are moving your existing project to Quasar from a Webpack v4 project, you might have some compatibility issues with 3rd party libraries. Webpack v5 removed the Node.js polyfills for the web client builds. If you are using packages for the web client that rely on Node.js API, you will get errors saying that some packages are missing. Examples: Buffer, crypto, os, path, stream, assert.

These need to be addressed by the package owners. But if you prefer not to wait and just want to run your app/website (with a bit of risk), then you can manually install node-polyfill-webpack-plugin (yarn add --dev node-polyfill-webpack-plugin) and reference it in quasar.config file > build > chainWebpack. Example:

const nodePolyfillWebpackPlugin from 'node-polyfill-webpack-plugin'

build: {
  chainWebpack (chain) {
    chain.plugin('node-polyfill').use(nodePolyfillWebpackPlugin)
  }
}

Webpack loaders

The build system uses Webpack, so it relies on using webpack loaders to handle different types of files (js, css, styl, scss, json, and so on). By default, the most used loaders are provided by default.

Installing loaders

Let’s take an example. You want to be able to import .json files. Out of the box, Quasar supplies json support so you don’t actually need to follow these steps, but for the sake of demonstrating how to add a loader, we’ll pretend Quasar doesn’t offer it.

So, you need a loader for it. You search Google to see what webpack loader you need. In this case, it’s “json-loader”. We first install it:

$ yarn add --dev json-loader

After installing your new loader, we want to tell Webpack to use it. So we edit the /quasar.config file and change build.extendWebpack() to add entries to module/rules for this new loader:

build: {
  extendWebpack (cfg) {
    cfg.module.rules.push({
      test: /\.json$/,
      loader: 'json-loader'
    })
  }
}

Equivalent with chainWebpack():

build: {
  chainWebpack (chain) {
    chain.module.rule('json')
      .test(/\.json$/)
      .use('json-loader')
        .loader('json-loader')
  }
}

And you’re done.

PostCSS

Styles in *.vue files (and all other style files) are piped through PostCSS by default, so you don’t need to use a specific loader for it.

By default, PostCSS is configured to use Autoprefixer. Take a look at /postcss.config.cjs where you can tweak it if you need to.

Pug

First, you need to install some dependencies:

$ yarn add --dev pug pug-plain-loader

Then you need to extend the webpack configuration through the /quasar.config file:

build: {
  extendWebpack (cfg) {
    cfg.module.rules.push({
      test: /\.pug$/,
      loader: 'pug-plain-loader'
    })
  }
}

Equivalent with chainWebpack():

build: {
  chainWebpack (chain) {
    chain.module.rule('pug')
      .test(/\.pug$/)
      .use('pug-plain-loader')
        .loader('pug-plain-loader')
  }
}

Coffeescript

If you are using Coffeescript then you need to EITHER disable ESLint OR tell ESLint which Vue components are using Coffeescript.

Note that vue-loader uses lang="coffee" to identify components which are using Coffeescript, but lang="coffee" is not recognizable for ESLint. Fortunately, ESLint (following traditional HTML) uses type="xxx" to identify the type of scripts. As long as a <script> tag has any type other than javascript, ESLint would mark the script as non-javascript, and skips linting it. Coffeescript’s convention is to use type="text/coffeescript" to identify itself. Therefore, in your Vue components which are using Coffeescript, using both lang and type to avoid ESLint warnings:

<template>
  ...
</template>
<script lang="coffee" type="text/coffeescript">
  ...
</script>