How to Customize Vue Webpack Loaders

One of the most unique features of Vue is the built-in support for other languages and pre-processors in .vue single-file-components. This allows you to use whatever pre-processor you’d like so long as it has an available webpack loader. Often the defaults are enough, but here we’ll show you how to add a new language (sort of) to Vue, and configure other ones.

Configuration

This assumes you’ve already got a basic Webpack config ready. (If not, use vue-cli’s webpack-simple template.)

Once you’ve got a basic build ready, open up your webpack.config.js or similar, and look for the vue-loader options.

...
{
  test: /\.vue$/,
  loader: 'vue-loader',
  options: {
  }
},
...

Now, for a given block in your template, Vue will attempt to find the matching loader for the language. ie. SASS becomes sass-loader and LESS -> less-loader. That’s all well and good, but often people want to use SCSS. And there’s no such thing as scss-loader.

Thankfully, vue-loader allows you to override the loader used for any language, and even add new languages.

We can add in support for SCSS using:

...
{
  test: /\.vue$/,
  loader: 'vue-loader',
  options: {
    loaders: {
      scss: {
        loader: 'sass-loader'
      }
    }
  }
},
...

And use it:

<template>
  ...
</template>

<style lang="scss">
  .i {
    &.can {
      &.use {
        &.scss {
          color: red;
        }
      }
    }
  }
</style>

If we want two separate configurations of the same loader, we can do that too. Let’s create a “new language” that is really just another configuration of scss-loader.

...
{
  test: /\.vue$/,
  loader: 'vue-loader',
  options: {
    loaders: {
      scss: {
        loader: 'sass-loader'
      },

      newscss: {
        loader: 'sass-loader',
        options: {
          includePaths: ['../../../somewhere/far/far/away']
        }
      }
    }
  }
},
...

And use it:

<template>
  ...
</template>

<style lang="newscss">
  @import 'starwars-styles';

  .i {
    &.can {
      &.use {
        &.scss {
          color: $font-color;
        }
      }
    }
  }
</style>

This pattern can be used with almost any other webpack loader. The only requirements are that loaders for scripts output valid JavaScript, loaders for styles output valid CSS, and loaders for HTML output valid HTML partials and handle vue-style attributes correctly. As a result, it’s trivial to use almost any pre-processor in Vue. Enjoy!