fix(@ngtools/webpack): add exclude override to tsconfig

Fix #3973

Author: filipesilva

packages/@ngtools/webpack/src/plugin.ts

@@ -122,35 +122,31 @@ export class AotPlugin implements Tapable {
       );
     }
 
+    // Default exclude to **/*.spec.ts files.
+    if (!options.hasOwnProperty('exclude')) {
+      options['exclude'] = ['**/*.spec.ts'];
+    }
+
+    // Add custom excludes to default TypeScript excludes.
+    if (options.hasOwnProperty('exclude')) {
+      // If the tsconfig doesn't contain any excludes, we must add the default ones before adding
+      // any extra ones (otherwise we'd include all of these which can cause unexpected errors).
+      // This is the same logic as present in TypeScript.
+      if (!tsConfigJson.exclude) {
+        tsConfigJson['exclude'] = ['node_modules', 'bower_components', 'jspm_packages'];
+        if (tsConfigJson.compilerOptions && tsConfigJson.compilerOptions.outDir) {
+          tsConfigJson.exclude.push(tsConfigJson.compilerOptions.outDir);
+        }
+      }
+
+      // Join our custom excludes with the existing ones.
+      tsConfigJson.exclude = tsConfigJson.exclude.concat(options.exclude);
+    }
+
     const tsConfig = ts.parseJsonConfigFileContent(
       tsConfigJson, ts.sys, basePath, null, this._tsConfigPath);
 
     let fileNames = tsConfig.fileNames;
-    if (options.hasOwnProperty('exclude')) {
-      let exclude: string[] = typeof options.exclude == 'string'
-          ? [options.exclude as string] : (options.exclude as string[]);
-
-      exclude.forEach((pattern: string) => {
-        const basePathPattern = '(' + basePath.replace(/\\/g, '/')
-            .replace(/[\-\[\]\/{}()+?.\\^$|*]/g, '\\$&') + ')?';
-        pattern = pattern
-          // Replace windows path separators with forward slashes.
-          .replace(/\\/g, '/')
-          // Escape characters that are used normally in regexes, except stars.
-          .replace(/[\-\[\]{}()+?.\\^$|]/g, '\\$&')
-          // Two stars replacement.
-          .replace(/\*\*/g, '(?:.*)')
-          // One star replacement.
-          .replace(/\*/g, '(?:[^/]*)')
-          // Escape characters from the basePath and make sure it's forward slashes.
-          .replace(/^/, basePathPattern);
-
-        const re = new RegExp('^' + pattern + '$');
-        fileNames = fileNames.filter(x => !x.replace(/\\/g, '/').match(re));
-      });
-    } else {
-      fileNames = fileNames.filter(fileName => !/\.spec\.ts$/.test(fileName));
-    }
     this._rootFilePath = fileNames;
 
     // Check the genDir. We generate a default gendir that's under basepath; it will generate