Merge pull request webpack-contrib#138 from shama/prefer-resolver

Add `preferPathResolver` option

Author: mzgoddard

Diff for: README.md

@@ -81,6 +81,16 @@ stylus: {
 
 where `~` resolves to `node_modules/`
 
+### Prefer webpack resolving
+
+`stylus-loader` currently prefers resolving paths with stylus's resovling utilities and then falling back to webpack when it can't find files. Use the `preferPathResolver` option with the value `'webpack'` to swap this. This has the benefit of using webpack's async resolving instead of stylus's sync resolving. If you have a lot of dependencies in your stylus files this'll let those dependencies be found in parallel.
+
+```js
+styus: {
+  preferPathResolver: 'webpack',
+}
+```
+
 ## Install
 
 `npm install stylus-loader stylus --save-dev`

Diff for: lib/pathcache.js

@@ -88,53 +88,69 @@ PathCache.prototype.allDeps = function() {
 function resolvers(options, webpackResolver) {
   var evaluator = new Evaluator(nodes.null, options);
   var whenWebpackResolver = whenNodefn.lift(webpackResolver);
-  return [
-    // Stylus's normal resolver for single files.
-    function(context, path) {
-      // Stylus adds .styl to paths for normal "paths" lookup if it isn't there.
-      if (!/.styl$/.test(path)) {
-        path += '.styl';
-      }
 
-      var paths = options.paths.concat(context);
-      var found = utils.find(path, paths, options.filename)
-      if (found) {
-        return normalizePaths(found);
-      }
-    },
-    // Stylus's normal resolver for node_modules packages. Cannot locate paths
-    // inside a package.
-    function(context, path) {
-      // Stylus calls the argument name. If it exists it should match the name
-      // of a module in node_modules.
-      if (!path) {
-        return null;
-      }
+  // Stylus's normal resolver for single files.
+  var stylusFile = function(context, path) {
+    // Stylus adds .styl to paths for normal "paths" lookup if it isn't there.
+    if (!/.styl$/.test(path)) {
+      path += '.styl';
+    }
 
-      var paths = options.paths.concat(context);
-      var found = utils.lookupIndex(path, paths, options.filename);
-      if (found) {
-        return {path: normalizePaths(found), index: true};
-      }
-    },
-    // Fallback to resolving with webpack's configured resovler.
-    function(context, path) {
-      // Follow the webpack stylesheet idiom of '~path' meaning a path in a
-      // modules folder and a unprefixed 'path' meaning a relative path like
-      // './path'.
-      path = loaderUtils.urlToRequest(path, options.root);
-      // First try with a '.styl' extension.
-      return whenWebpackResolver(context, path + '.styl')
-        // If the user adds ".styl" to resolve.extensions, webpack can find
-        // index files like stylus but it uses all of webpack's configuration,
-        // by default for example the module could be web_modules.
-        .catch(function() { return whenWebpackResolver(context, path); })
-        .catch(function() { return null; })
-        .then(function(result) {
-          return Array.isArray(result) && result[1] && result[1].path || result
-        });
+    var paths = options.paths.concat(context);
+    var found = utils.find(path, paths, options.filename)
+    if (found) {
+      return normalizePaths(found);
+    }
+  };
+
+  // Stylus's normal resolver for node_modules packages. Cannot locate paths
+  // inside a package.
+  var stylusIndex = function(context, path) {
+    // Stylus calls the argument name. If it exists it should match the name
+    // of a module in node_modules.
+    if (!path) {
+      return null;
     }
-  ];
+
+    var paths = options.paths.concat(context);
+    var found = utils.lookupIndex(path, paths, options.filename);
+    if (found) {
+      return {path: normalizePaths(found), index: true};
+    }
+  };
+
+  // Fallback to resolving with webpack's configured resovler.
+  var webpackResolve = function(context, path) {
+    // Follow the webpack stylesheet idiom of '~path' meaning a path in a
+    // modules folder and a unprefixed 'path' meaning a relative path like
+    // './path'.
+    path = loaderUtils.urlToRequest(path, options.root);
+    // First try with a '.styl' extension.
+    return whenWebpackResolver(context, path + '.styl')
+      // If the user adds ".styl" to resolve.extensions, webpack can find
+      // index files like stylus but it uses all of webpack's configuration,
+      // by default for example the module could be web_modules.
+      .catch(function() { return whenWebpackResolver(context, path); })
+      .catch(function() { return null; })
+      .then(function(result) {
+        return Array.isArray(result) && result[1] && result[1].path || result
+      });
+  };
+
+  if (options.preferPathResolver === 'webpack') {
+    return [
+      webpackResolve,
+      stylusFile,
+      stylusIndex
+    ];
+  }
+  else {
+    return [
+      stylusFile,
+      stylusIndex,
+      webpackResolve
+    ];
+  }
 }
 
 function reduceResolvers(resolvers, context, path) {