Importing Sass through npm

Question

Currently in our Sass files we have something like the following:

@import "../../node_modules/some-module/sass/app";

This is bad, because we're not actually sure of the path: it could be ../node_modules, it could be ../../../../../node_modules, because of how npm installs stuff.

Is there a way in Sass that we can search up until we find node_modules? Or even a proper way of including Sass through npm?

Answer 1

You can use a Sass importer function to do so. Cf. https://github.com/sass/node-sass#importer--v200.

The following example illustrates node-sass@3.0.0 with node@0.12.2:

Install the bower dependency:

$ bower install sass-mq
$ npm install sass/node-sass#3.0.0-pre

The Sass file:

@import 'sass-mq/mq';

body {
  @include mq($from: mobile) {
    color: red;
  }
  @include mq($until: tablet) {
    color: blue;
  }
}

The node renderer file:

'use strict';

var sass = require('node-sass');
var path = require('path');
var fs = require('fs');

var options = {
  file: './sample.scss',
  importer: function bowerModule(url, file, done){
    var bowerComponent = url.split(path.sep)[0];

    if (bowerComponent !== url) {
      fs.access(path.join(__dirname, 'bower_components', bowerComponent), fs.R_OK, function(err){
        if (err) {
          return done({ file: url });
        }

        var newUrl = path.join(__dirname, 'bower_components', url);

        done({ file: newUrl });
      })
    }
    else {
      done({ file: url });
    }
  }
};

sass.render(options, function(err, result){
  if (err) {
    console.error(err);
    return;
  }

  console.log(result.css.toString());
});

This one is simple and not recursive. The require.resolve function could help to deal with the tree – or wait until npm@3.0.0 to benefit from the flat dependency tree.

Answer 2

I made the sass-npm module specifically for this.

npm install sass-npm

In your SASS:

// Since node_modules/npm-module-name/style.scss exists, this will be imported.
@import "npm-module-name";

// Since just-a-sass-file isn't an installed npm module, it will be imported as a regular SCSS file.
@import "just-a-sass-file";

I normally use gulp-sass (which has the same 'importer' option as regular SASS)

var gulp = require('gulp'),
    sass = require('gulp-sass'),
    sassNpm = require('sass-npm')();

Then, in your .pipe(sass()), add the importer as an option:

.pipe(sass({
    paths: ['public/scss'],
    importer: sassNpm.importer,
}))

Answer 3

As Oncle Tom mentioned, the new version of Sass has this new importer option, where every "import" you do on your Sass file will go first through this method. That means that you can then modify the actual url of this method.

I've used require.resolve to locate the actual module entry file.
Have a look at my gulp task and see if it helps you:

'use strict';

var path       = require('path'),
    gulp       = require('gulp'),
    sass       = require('gulp-sass');

var aliases = {};

/**
 * Will look for .scss|sass files inside the node_modules folder
 */
function npmModule(url, file, done) {
  // check if the path was already found and cached
  if(aliases[url]) {
    return done({ file:aliases[url] });
  }

  // look for modules installed through npm
  try {
    var newPath = path.relative('./css', require.resolve(url));
    aliases[url] = newPath; // cache this request
    return done({ file:newPath });
  } catch(e) {
    // if your module could not be found, just return the original url
    aliases[url] = url;
    return done({ file:url });
  }
}

gulp.task("style", function() {
  return gulp.src('./css/app.scss')
    .pipe(sass({ importer:npmModule }))
    .pipe(gulp.dest('./css'));
});

Now let's say you installed inuit-normalize using node. You can simply "require" it on your Sass file:

@import "inuit-normalize";

I hope that helps you and others. Because adding relative paths is always a pain in the ass :)

Answer 4

You can add another includePaths to your render options.

Plain example

Snippet based on example from Oncle Tom.

var options = {
  file: './sample.scss',
  includePaths: [
    path.join(__dirname, 'bower_components'), // bower
    path.join(__dirname, 'node_modules') // npm
  ]
};

sass.render(options, function(err, result){
  console.log(result.css.toString());
});

That should do. You can include the files from package using @import "my-cool-package/super-grid

Webpack and scss-loader example

{
  test: /\.scss$/, 
  loader: 'style!css!autoprefixer?browsers=last 2 version!sass?outputStyle=expanded&sourceMap=true&sourceMapContents=true&includePaths[]=./node_modules' 
},

Notice the last argument, includePaths has to be array. Keep in mind to use right format

Answer 5

If you are looking for a handy answer in 2017 and are using Webpack, this was the easiest I found.

Suppose your module path is like:

node_modules/some-module/sass/app

Then in your main scss file you can use:

@import "~some-module/sass/app";

Tilde operator shall resolve any import as a module.