feat: prefer sass (dart-sass) by default (#826)

BREAKING CHANGE: prefer `sass` (`dart-sass`) by default

README.md

@@ -24,10 +24,10 @@ Loads a Sass/SCSS file and compiles it to CSS.
 To begin, you'll need to install `sass-loader`:
 
 ```console
-npm install sass-loader node-sass webpack --save-dev
+npm install sass-loader sass webpack --save-dev
 ```
 
-`sass-loader` requires you to install either [Node Sass](https://github.com/sass/node-sass) or [Dart Sass](https://github.com/sass/dart-sass) on your own (more documentation can be found below).
+`sass-loader` requires you to install either [Dart Sass](https://github.com/sass/dart-sass) on your own (more documentation can be found below) or [Node Sass](https://github.com/sass/node-sass).
 This allows you to control the versions of all your dependencies, and to choose which Sass implementation to use.
 
 Chain the `sass-loader` with the [css-loader](https://github.com/webpack-contrib/css-loader) and the [style-loader](https://github.com/webpack-contrib/style-loader) to immediately apply all styles to the DOM or the [mini-css-extract-plugin](https://github.com/webpack-contrib/mini-css-extract-plugin) to extract it into a separate file.
@@ -106,10 +106,12 @@ Thankfully there are a two solutions to this problem:
 
 ### `implementation`
 
+Default: `sass`
+
 The special `implementation` option determines which implementation of Sass to use.
 
 By default the loader resolve the implementation based on your dependencies.
-Just add required implementation to `package.json` (`node-sass` or `sass` package) and install dependencies.
+Just add required implementation to `package.json` (`sass` or `node-sass` package) and install dependencies.
 
 Example where the `sass-loader` loader uses the `sass` (`dart-sass`) implementation:
 
@@ -137,9 +139,10 @@ Example where the `sass-loader` loader uses the `node-sass` implementation:
 }
 ```
 
-Beware the situation when `node-sass` and `sass` were installed! By default the `sass-loader` prefers `node-sass`. In order to avoid this situation you can use the `implementation` option.
+Beware the situation when `node-sass` and `sass` were installed! By default the `sass-loader` prefers `sass`.
+In order to avoid this situation you can use the `implementation` option.
 
-The `implementation` options either accepts `node-sass` or `sass` (`Dart Sass`) as a module.
+The `implementation` options either accepts `sass` (`Dart Sass`) or `node-sass` as a module.
 
 For example, to use Dart Sass, you'd pass:
 
@@ -245,19 +248,20 @@ module.exports = {
 
 Type: `Object|Function`
 
-Options for [Node Sass](https://github.com/sass/node-sass) or [Dart Sass](http://sass-lang.com/dart-sass) implementation.
+Options for [Dart Sass](http://sass-lang.com/dart-sass) or [Node Sass](https://github.com/sass/node-sass) implementation.
 
 > ℹ️ The `indentedSyntax` option has `true` value for the `sass` extension.
 
 > ℹ️ Options such as `file` and `outFile` are unavailable.
 
 > ℹ We recommend not to use the `sourceMapContents`, `sourceMapEmbed`, `sourceMapRoot` options because `sass-loader` automatically sets these options.
 
-There is a slight difference between the `node-sass` and `sass` (`Dart Sass`) options.
+There is a slight difference between the `sass` (`dart-sass`) and `node-sass` options.
+
 Please consult documentation before using them:
 
-- [Node Sass documentation](https://github.com/sass/node-sass/#options) for all available `node-sass` options.
 - [Dart Sass documentation](https://github.com/sass/dart-sass#javascript-api) for all available `sass` options.
+- [Node Sass documentation](https://github.com/sass/node-sass/#options) for all available `node-sass` options.
 
 #### `Object`
 

src/getDefaultSassImplementation.js

@@ -1,14 +1,14 @@
 function getDefaultSassImplementation() {
-  let sassImplPkg = 'node-sass';
+  let sassImplPkg = 'sass';
 
   try {
-    require.resolve('node-sass');
+    require.resolve('sass');
   } catch (error) {
     try {
-      require.resolve('sass');
-      sassImplPkg = 'sass';
-    } catch (ignoreError) {
+      require.resolve('node-sass');
       sassImplPkg = 'node-sass';
+    } catch (ignoreError) {
+      sassImplPkg = 'sass';
     }
   }
 

test/implementation-option.test.js

@@ -69,8 +69,8 @@ describe('implementation option', () => {
     expect(getWarnings(stats)).toMatchSnapshot('warnings');
     expect(getErrors(stats)).toMatchSnapshot('errors');
 
-    expect(nodeSassSpy).toHaveBeenCalledTimes(1);
-    expect(dartSassSpy).toHaveBeenCalledTimes(0);
+    expect(nodeSassSpy).toHaveBeenCalledTimes(0);
+    expect(dartSassSpy).toHaveBeenCalledTimes(1);
   });
 
   it('should throw an error when the "node-sass" package is an incompatible version', async () => {

test/validate-options.test.js

@@ -49,9 +49,6 @@ it('validate options', () => {
   ).not.toThrow();
   expect(() => validate({ sassOptions: () => {} })).not.toThrow();
   expect(() => validate({ sassOptions: true })).toThrowErrorMatchingSnapshot();
-  expect(() =>
-    validate({ sassOptions: { fiber: { mock: true } } })
-  ).not.toThrow();
   expect(() =>
     validate({ sassOptions: { indentWidth: 6, linefeed: 'crlf' } })
   ).not.toThrow();