Make this package implementation-agnostic

README.md

@@ -13,7 +13,7 @@ Only [Active LTS and Current releases][1] are supported.
 # Install
 
 ```
-npm install gulp-sass --save-dev
+npm install node-sass gulp-sass --save-dev
 ```
 
 # Basic Usage
@@ -26,6 +26,8 @@ Something like this will compile your Sass files:
 var gulp = require('gulp');
 var sass = require('gulp-sass');
 
+sass.compiler = require('node-sass');
+
 gulp.task('sass', function () {
   return gulp.src('./sass/**/*.scss')
     .pipe(sass().on('error', sass.logError))
@@ -45,6 +47,8 @@ You can also compile synchronously, doing something like this:
 var gulp = require('gulp');
 var sass = require('gulp-sass');
 
+sass.compiler = require('node-sass');
+
 gulp.task('sass', function () {
   return gulp.src('./sass/**/*.scss')
     .pipe(sass.sync().on('error', sass.logError))
@@ -56,9 +60,36 @@ gulp.task('sass:watch', function () {
 });
 ```
 
+You can choose whether to use [Dart Sass][] or [Node Sass][] by setting the `sass.compiler` property. Node Sass will be used by default, but it's strongly recommended that you set it explicitly for forwards-compatibility in case the default ever changes.
+
+[Dart Sass]: http://sass-lang.com/dart-sass
+[Node Sass]: https://github.com/sass/node-sass
+
+Note that when using Dart Sass, **synchronous compilation is twice as fast as asynchronous compilation** by default, due to the overhead of asynchronous callbacks. To avoid this overhead, you can use the [`fibers`](https://www.npmjs.com/package/fibers) package to call asynchronous importers from the synchronous code path. To enable this, pass the `Fiber` class to the `fiber` option:
+
+```javascript
+'use strict';
+
+var Fiber = require('fibers');
+var gulp = require('gulp');
+var sass = require('gulp-sass');
+
+sass.compiler = require('sass');
+
+gulp.task('sass', function () {
+  return gulp.src('./sass/**/*.scss')
+    .pipe(sass({fiber: Fiber}).on('error', sass.logError))
+    .pipe(gulp.dest('./css'));
+});
+
+gulp.task('sass:watch', function () {
+  gulp.watch('./sass/**/*.scss', ['sass']);
+});
+```
+
 ## Options
 
-Pass in options just like you would for [`node-sass`](https://github.com/sass/node-sass#options); they will be passed along just as if you were using `node-sass`. Except for the `data` option which is used by gulp-sass internally. Using the `file` option is also unsupported and results in undefined behaviour that may change without notice.
+Pass in options just like you would for [Node Sass](https://github.com/sass/node-sass#options); they will be passed along just as if you were using Node Sass. Except for the `data` option which is used by gulp-sass internally. Using the `file` option is also unsupported and results in undefined behaviour that may change without notice.
 
 For example:
 
@@ -111,10 +142,13 @@ gulp.task('sass', function () {
 
 # Issues
 
-`gulp-sass` is a very light-weight wrapper around [`node-sass`](https://github.com/sass/node-sass), which in turn is a Node binding for [`libsass`](https://github.com/sass/libsass), which in turn is a port of [`Sass`](https://github.com/sass/sass). Because of this, the issue you're having likely isn't a `gulp-sass` issue, but an issue with one of those three projects.
+`gulp-sass` is a very light-weight wrapper around either [Dart Sass][] or [Node Sass][] (which in turn is a Node binding for [LibSass][]). Because of this, the issue you're having likely isn't a `gulp-sass` issue, but an issue with one those projects or with [Sass][] as a whole.
+
+[LibSass]: https://sass-lang.com/libsass
+[Sass]: https://sass-lang.com
 
-If you have a feature request/question how Sass works/concerns on how your Sass gets compiled/errors in your compiling, it's likely a `libsass` or `Sass` issue and you should file your issue with one of those projects.
+If you have a feature request/question how Sass works/concerns on how your Sass gets compiled/errors in your compiling, it's likely a Dart Sass or LibSass issue and you should file your issue with one of those projects.
 
-If you're having problems with the options you're passing in, it's likely a `node-sass` or `libsass` issue and you should file your issue with one of those projects.
+If you're having problems with the options you're passing in, it's likely a Dart Sass or Node Sass issue and you should file your issue with one of those projects.
 
 We may, in the course of resolving issues, direct you to one of these other projects. If we do so, please follow up by searching that project's issue queue (both open and closed) for your problem and, if it doesn't exist, filing an issue with them.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gulp-sass",
-  "version": "4.0.1",
+  "version": "4.0.2",
   "description": "Gulp plugin for sass",
   "main": "index.js",
   "engines": {