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node_modules/sass-loader/lib/loader.js

@@ -1,18 +1,14 @@
 "use strict";
 
-const sass = require("node-sass");
 const path = require("path");
 const async = require("neo-async");
 const formatSassError = require("./formatSassError");
 const webpackImporter = require("./webpackImporter");
 const normalizeOptions = require("./normalizeOptions");
 const pify = require("pify");
+const semver = require("semver");
 
-// This queue makes sure node-sass leaves one thread available for executing
-// fs tasks when running the custom importer code.
-// This can be removed as soon as node-sass implements a fix for this.
-const threadPoolSize = process.env.UV_THREADPOOL_SIZE || 4;
-const asyncSassJobQueue = async.queue(sass.render, threadPoolSize - 1);
+let nodeSassJobQueue = null;
 
 /**
  * The sass-loader makes node-sass available to webpack modules.
@@ -47,8 +43,9 @@ function sassLoader(content) {
         return;
     }
 
-    // start the actual rendering
-    asyncSassJobQueue.push(options, (err, result) => {
+    const render = getRenderFuncFromSassImpl(options.implementation || require("node-sass"));
+
+    render(options, (err, result) => {
         if (err) {
             formatSassError(err, this.resourcePath);
             err.file && this.dependency(err.file);
@@ -80,4 +77,48 @@ function sassLoader(content) {
     });
 }
 
+/**
+ * Verifies that the implementation and version of Sass is supported by this loader.
+ *
+ * @param {Object} module
+ * @returns {Function}
+ */
+function getRenderFuncFromSassImpl(module) {
+    const info = module.info;
+    const components = info.split("\t");
+
+    if (components.length < 2) {
+        throw new Error("Unknown Sass implementation \"" + info + "\".");
+    }
+
+    const implementation = components[0];
+    const version = components[1];
+
+    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 + "\".");
+}
+
 module.exports = sassLoader;