fix(webpack): Aliased module paths now properly map to the correct au…

…relia-loader module id

src/PreserveModuleNamePlugin.ts

@@ -28,7 +28,7 @@ export class PreserveModuleNamePlugin {
             modulesBeforeConcat.splice(i--, 1, ...m["modules"]);
         }
 
-        for (let module of getPreservedModules(modules)) {
+        for (let module of getPreservedModules(modules, alias)) {
           // Even though it's imported by Aurelia, it's still possible that the module
           // became the _root_ of a ConcatenatedModule.
           // We use `constructor.name` rather than `instanceof` for compat. with Webpack 2.
@@ -66,14 +66,36 @@ export class PreserveModuleNamePlugin {
   }
 };
 
-function getPreservedModules(modules: Webpack.Module[]) {      
+function getPreservedModules(modules: Webpack.Module[], aliases: {[key: string]: string } | null) {
   return new Set(
     modules.filter(m => {
       // Some modules might have [preserveModuleName] already set, see ConventionDependenciesPlugin.
       let value = m[preserveModuleName];      
       for (let r of m.reasons) {
         if (!r.dependency[preserveModuleName]) continue;
         value = true;
+
+        // Handle aliases
+        const raw: string | undefined = r.module && r.module.rawRequest;
+        const ext: string | RegExpMatchArray | null = m.rawRequest && m.rawRequest.match(/^.+(\.\w+$)/);
+        if (aliases && raw && ext) {
+          const alias_matches: string[] = Object.keys(aliases).filter((a: string): boolean => {
+            // Absolute?
+            if (a[a.length - 1] === '$' && a === `${raw}$`) {
+              return true;
+            }
+
+            return !!(raw.match(new RegExp(`^${a}/`)));
+          });
+
+          // Invalid?
+          if (alias_matches.length > 1) throw new Error(`Incorrect alias usage. "${raw}" is duplicated in ${alias_matches}`);
+          else if (alias_matches.length === 1 && ext[1]) {
+            m[exports.preserveModuleName] = `${raw}${ext[1]}`;
+            return true;
+          }
+        }
+
         let req = removeLoaders((r.dependency as ModuleDependency).request);
         // We try to find an absolute string and set that as the module [preserveModuleName], as it's the best id.
         if (req && !req.startsWith(".")) {