refactor: code (#745)

jest.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+  testEnvironment: 'node',
+};

src/getRenderFunctionFromSassImplementation.js

@@ -1,64 +1,33 @@
-import semver from 'semver';
 import async from 'neo-async';
 
 let nodeSassJobQueue = null;
 
 /**
  * Verifies that the implementation and version of Sass is supported by this loader.
  *
- * @param {Object} module
+ * @param {Object} implementation
  * @returns {Function}
  */
-function getRenderFunctionFromSassImplementation(module) {
-  const { info } = module;
+function getRenderFunctionFromSassImplementation(implementation) {
+  const isDartSass = implementation.info.includes('dart-sass');
 
-  if (!info) {
-    throw new Error('Unknown Sass implementation.');
+  if (isDartSass) {
+    return implementation.render.bind(implementation);
   }
 
-  const components = info.split('\t');
+  // There is an issue with node-sass when async custom importers are used
+  // See https://github.com/sass/node-sass/issues/857#issuecomment-93594360
+  // We need to use a job queue to make sure that one thread is always available to the UV lib
+  if (nodeSassJobQueue === null) {
+    const threadPoolSize = Number(process.env.UV_THREADPOOL_SIZE || 4);
 
-  if (components.length < 2) {
-    throw new Error(`Unknown Sass implementation "${info}".`);
+    nodeSassJobQueue = async.queue(
+      implementation.render.bind(implementation),
+      threadPoolSize - 1
+    );
   }
 
-  const [implementation, version] = components;
-
-  if (!semver.valid(version)) {
-    throw new Error(`Invalid Sass version "${version}".`);
-  }
-
-  if (implementation === 'dart-sass') {
-    if (!semver.satisfies(version, '^1.3.0')) {
-      throw new Error(
-        `Dart Sass version ${version} is incompatible with ^1.3.0.`
-      );
-    }
-
-    return module.render.bind(module);
-  } else if (implementation === 'node-sass') {
-    if (!semver.satisfies(version, '^4.0.0')) {
-      throw new Error(
-        `Node Sass version ${version} is incompatible with ^4.0.0.`
-      );
-    }
-
-    // There is an issue with node-sass when async custom importers are used
-    // See https://github.com/sass/node-sass/issues/857#issuecomment-93594360
-    // We need to use a job queue to make sure that one thread is always available to the UV lib
-    if (nodeSassJobQueue === null) {
-      const threadPoolSize = Number(process.env.UV_THREADPOOL_SIZE || 4);
-
-      nodeSassJobQueue = async.queue(
-        module.render.bind(module),
-        threadPoolSize - 1
-      );
-    }
-
-    return nodeSassJobQueue.push.bind(nodeSassJobQueue);
-  }
-
-  throw new Error(`Unknown Sass implementation "${implementation}".`);
+  return nodeSassJobQueue.push.bind(nodeSassJobQueue);
 }
 
 export default getRenderFunctionFromSassImplementation;

src/getSassImplementation.js

@@ -0,0 +1,48 @@
+import semver from 'semver';
+
+import getDefaultSassImplementation from './getDefaultSassImplementation';
+
+function getSassImplementation(implementation) {
+  let resolvedImplementation = implementation;
+
+  if (!resolvedImplementation) {
+    // eslint-disable-next-line no-param-reassign
+    resolvedImplementation = getDefaultSassImplementation();
+  }
+
+  const { info } = resolvedImplementation;
+
+  if (!info) {
+    throw new Error('Unknown Sass implementation.');
+  }
+
+  const infoParts = info.split('\t');
+
+  if (infoParts.length < 2) {
+    throw new Error(`Unknown Sass implementation "${info}".`);
+  }
+
+  const [implementationName, version] = infoParts;
+
+  if (implementationName === 'dart-sass') {
+    if (!semver.satisfies(version, '^1.3.0')) {
+      throw new Error(
+        `Dart Sass version ${version} is incompatible with ^1.3.0.`
+      );
+    }
+
+    return resolvedImplementation;
+  } else if (implementationName === 'node-sass') {
+    if (!semver.satisfies(version, '^4.0.0')) {
+      throw new Error(
+        `Node Sass version ${version} is incompatible with ^4.0.0.`
+      );
+    }
+
+    return resolvedImplementation;
+  }
+
+  throw new Error(`Unknown Sass implementation "${implementationName}".`);
+}
+
+export default getSassImplementation;

src/index.js

@@ -4,9 +4,9 @@ import validateOptions from 'schema-utils';
 import { getOptions } from 'loader-utils';
 
 import schema from './options.json';
+import getSassImplementation from './getSassImplementation';
 import getSassOptions from './getSassOptions';
 import webpackImporter from './webpackImporter';
-import getDefaultSassImplementation from './getDefaultSassImplementation';
 import getRenderFunctionFromSassImplementation from './getRenderFunctionFromSassImplementation';
 import SassError from './SassError';
 
@@ -24,6 +24,8 @@ function loader(content) {
     baseDataPath: 'options',
   });
 
+  const implementation = getSassImplementation(options.implementation);
+
   const callback = this.async();
   const addNormalizedDependency = (file) => {
     // node-sass returns POSIX paths
@@ -55,9 +57,7 @@ function loader(content) {
     return;
   }
 
-  const render = getRenderFunctionFromSassImplementation(
-    options.implementation || getDefaultSassImplementation()
-  );
+  const render = getRenderFunctionFromSassImplementation(implementation);
 
   render(sassOptions, (error, result) => {
     if (error) {

test/__snapshots__/implementation-option.test.js.snap

@@ -26,7 +26,7 @@ Error: Unknown Sass implementation "strange-sass".
 
 exports[`implementation option should throw an error when the "info" is unparseable #2 1`] = `
 [Error: Module build failed (from ../src/cjs.js):
-Error: Invalid Sass version "1".
+Error: Node Sass version 1 is incompatible with ^4.0.0.
     at ReplacedStackEntry
     at ReplacedStackEntry]
 `;