fix(@angular-devkit/build-optimizer): fix hoisted class declarations

The problem is that hoisted classes dont have the same name, so we need to change
the regex, and to check the end of it for the class name.

Also added a test to verify this works (based on RxJS issue).

Also refactored the complex regex to make a bit more sense.

Fixes #214.

Author: hansl

packages/angular_devkit/build_optimizer/src/transforms/prefix-classes.ts

@@ -5,22 +5,37 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import { satisfies } from 'semver';
 import * as ts from 'typescript';
 
 
 export function testPrefixClasses(content: string) {
+  const exportVarSetter = /(?:export )?(?:var|const)\s+(\S+)\s*=\s*/;
+  const multiLineComment = /\s*(?:\/\*[\s\S]*?\*\/)?\s*/;
+  const newLine = /\s*\r?\n\s*/;
+
   const regexes = [
-    // tslint:disable-next-line:max-line-length
-    /^(?:export )?(var (\S+) = )(?:\/\*\* @class \*\/ )?(\(function \(\) \{\r?\n(?:\s+(?:\/\*\*| \*|\*\/|\/\/)[^\r?\n]*\r?\n)*\s+function \2\([^\)]*\) \{\r?\n)/,
-    /^(?:export )?(var (\S+) = )(?:\/\*\* @class \*\/ )?(\(function \(_super\) \{\r?\n\s+\w*__extends\(\w+, _super\);\r?\n)/,
-  ];
+    [
+      /^/,
+      exportVarSetter, multiLineComment,
+      /\(/, multiLineComment,
+      /\s*function \(\) {/, newLine,
+      multiLineComment,
+      /function \1\([^\)]*\) \{/, newLine,
+    ],
+    [
+      /^/,
+      exportVarSetter, multiLineComment,
+      /\(/, multiLineComment,
+      /\s*function \(_super\) {/, newLine,
+      /\w*__extends\(\w+, _super\);/,
+    ],
+  ].map(arr => new RegExp(arr.map(x => x.source).join(''), 'm'));
 
   return regexes.some((regex) => regex.test(content));
 }
 
 const superParameterName = '_super';
-const extendsHelperName = (satisfies(ts.version, '< 2.5') ? '_' : '') + '__extends';
+const extendsHelperName = '__extends';
 
 export function getPrefixClassesTransformer(): ts.TransformerFactory<ts.SourceFile> {
   return (context: ts.TransformationContext): ts.Transformer<ts.SourceFile> => {
@@ -218,7 +233,7 @@ function isDownleveledClass(node: ts.Node): boolean {
   const extendCallExpression = firstStatement.expression;
 
   if (!isIdentifier(extendCallExpression.expression)
-      || extendCallExpression.expression.text !== extendsHelperName) {
+      || !extendCallExpression.expression.text.endsWith(extendsHelperName)) {
     return false;
   }
 
@@ -236,6 +251,6 @@ function isDownleveledClass(node: ts.Node): boolean {
 
   return isFunctionDeclaration(secondStatement)
          && secondStatement.name !== undefined
-         && secondStatement.name.text === className
+         && className.endsWith(secondStatement.name.text)
          && returnStatement.expression.text === secondStatement.name.text;
 }

packages/angular_devkit/build_optimizer/src/transforms/prefix-classes_spec.ts

@@ -217,4 +217,65 @@ describe('prefix-classes', () => {
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
   });
 
+  it('fixes the RxJS use case (issue #214)', () => {
+    const input = `
+      var ExtendedClass = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
+        __extends(ExtendedClass, _super);
+        function ExtendedClass() {
+            return _super !== null && _super.apply(this, arguments) || this;
+        }
+        return ExtendedClass;
+      }(StaticTestCase));
+
+      /**
+       * We need this JSDoc comment for affecting ESDoc.
+       * @ignore
+       * @extends {Ignored}
+       */
+      var zip_ZipSubscriber = /*@__PURE__*/ (/*@__PURE__*/ function (_super) {
+          zip___extends(ZipSubscriber, _super);
+          function ZipSubscriber(destination, project, values) {
+              if (values === void 0) {
+                  values = Object.create(null);
+              }
+              _super.call(this, destination);
+              this.iterators = [];
+              this.active = 0;
+              this.project = (typeof project === 'function') ? project : null;
+              this.values = values;
+          }
+          return ZipSubscriber;
+      }(Subscriber));
+    `;
+    const output = `
+      var ExtendedClass = /*@__PURE__*/ (function (_super) {
+        __extends(ExtendedClass, _super);
+        function ExtendedClass() {
+            return _super !== null && _super.apply(this, arguments) || this;
+        }
+        return ExtendedClass;
+      }(StaticTestCase));
+
+      /**
+       * We need this JSDoc comment for affecting ESDoc.
+       * @ignore
+       * @extends {Ignored}
+       */
+      var zip_ZipSubscriber = /*@__PURE__*/ (function (_super) {
+          zip___extends(ZipSubscriber, _super);
+          function ZipSubscriber(destination, project, values) {
+              if (values === void 0) {
+                  values = Object.create(null);
+              }
+              _super.call(this, destination);
+              this.iterators = [];
+              this.active = 0;
+              this.project = (typeof project === 'function') ? project : null;
+              this.values = values;
+          }
+          return ZipSubscriber;
+      }(Subscriber));
+    `;
+    expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
+  });
 });