fix(@angular-devkit/build-optimizer): prefix renamed classes

Module concatenation may rename classes with the same name. The renaming logic is specific to the bundler so we can't really foresee it.

But the fact remains that the inner function declaration doesn't need to have the same name as the outer one.

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

@@ -11,7 +11,7 @@ import * as ts from 'typescript';
  * @deprecated From 0.9.0
  */
 export function testPrefixClasses(content: string) {
-  const exportVarSetter = /(?:export )?(?:var|const)\s+(\S+)\s*=\s*/;
+  const exportVarSetter = /(?:export )?(?:var|const)\s+(?:\S+)\s*=\s*/;
   const multiLineComment = /\s*(?:\/\*[\s\S]*?\*\/)?\s*/;
   const newLine = /\s*\r?\n\s*/;
 
@@ -22,7 +22,7 @@ export function testPrefixClasses(content: string) {
       /\(/, multiLineComment,
       /\s*function \(\) {/, newLine,
       multiLineComment,
-      /function \1\([^\)]*\) \{/, newLine,
+      /function (?:\S+)\([^\)]*\) \{/, newLine,
     ],
     [
       /^/,
@@ -142,9 +142,6 @@ function isDownleveledClass(node: ts.Node): boolean {
     return false;
   }
 
-  // The variable name should be the class name.
-  const className = variableDeclaration.name.text;
-
   const firstStatement = functionStatements[0];
 
   // find return statement - may not be last statement
@@ -166,7 +163,6 @@ function isDownleveledClass(node: ts.Node): boolean {
     // potential non-extended class or wrapped es2015 class
     return (ts.isFunctionDeclaration(firstStatement) || ts.isClassDeclaration(firstStatement))
            && firstStatement.name !== undefined
-           && firstStatement.name.text === className
            && returnStatement.expression.text === firstStatement.name.text;
   } else if (functionExpression.parameters.length !== 1) {
     return false;
@@ -216,6 +212,5 @@ function isDownleveledClass(node: ts.Node): boolean {
 
   return ts.isFunctionDeclaration(secondStatement)
          && secondStatement.name !== undefined
-         && className.endsWith(secondStatement.name.text)
          && returnStatement.expression.text === secondStatement.name.text;
 }

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

@@ -173,6 +173,26 @@ describe('prefix-classes', () => {
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
   });
 
+  it('prefix TS 2.5 - 2.6 renamed downlevel class', () => {
+    const input = tags.stripIndent`
+      var ComponentFactoryResolver$1 = /** @class */ (function () {
+        function ComponentFactoryResolver$$1() {
+        }
+        return ComponentFactoryResolver$$1;
+      }());
+    `;
+    const output = tags.stripIndent`
+      var ComponentFactoryResolver$1 = /** @class */ /*@__PURE__*/ (function () {
+        function ComponentFactoryResolver$$1() {
+        }
+        return ComponentFactoryResolver$$1;
+      }());
+    `;
+
+    expect(testPrefixClasses(input)).toBeTruthy();
+    expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
+  });
+
   it('prefix TS 2.5 - 2.6 downlevel class with static variable', () => {
     const input = tags.stripIndent`
       var StaticTestCase = /** @class */ (function () {