From 59d80f52be35217850a2b130b0cfacaf0f51f3c0 Mon Sep 17 00:00:00 2001
From: Alan Agius <alan.agius4@gmail.com>
Date: Fri, 23 Aug 2019 20:35:42 +0200
Subject: [PATCH] fix(@angular-devkit/build-optimizer): replace multiple tslib
 helpers (#15400)

Inlined tslib helpers can be suffixed with `$` and a number when having multiple helpers in the same file.

With this change we will replace all tslib inline helpers to imports from `tslib`
---
 .../src/transforms/import-tslib.ts            | 23 +++++---
 .../src/transforms/import-tslib_spec.ts       | 54 +++++++++++++++++++
 2 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/packages/angular_devkit/build_optimizer/src/transforms/import-tslib.ts b/packages/angular_devkit/build_optimizer/src/transforms/import-tslib.ts
index 4b57fc9e039e..27a43e80b5c9 100644
--- a/packages/angular_devkit/build_optimizer/src/transforms/import-tslib.ts
+++ b/packages/angular_devkit/build_optimizer/src/transforms/import-tslib.ts
@@ -12,7 +12,7 @@ import { isHelperName } from '../helpers/ast-utils';
  * @deprecated From 0.9.0
  */
 export function testImportTslib(content: string) {
-  const regex = /var (__extends|__decorate|__metadata|__param) = \(.*\r?\n\s+(.*\r?\n)*\s*\};/;
+  const regex = /var (__extends|__decorate|__metadata|__param)(\$\d+)? = \(.*\r?\n\s+(.*\r?\n)*\s*\};/;
 
   return regex.test(content);
 }
@@ -34,11 +34,18 @@ export function getImportTslibTransformer(): ts.TransformerFactory<ts.SourceFile
           const declarations = node.declarationList.declarations;
 
           if (declarations.length === 1 && ts.isIdentifier(declarations[0].name)) {
-            const name = (declarations[0].name as ts.Identifier).text;
+            const name = declarations[0].name.text;
 
-            if (isHelperName(name)) {
+            // In FESM's when not using importHelpers there might be nultiple in the same file.
+            // Example:
+            // var __decorate$1 = '';
+            // var __decorate$2 = '';
+            const helperName = name.split(/\$\d+$/)[0];
+
+            if (isHelperName(helperName)) {
               // TODO: maybe add a few more checks, like checking the first part of the assignment.
-              const tslibImport = createTslibImport(name, useRequire);
+              const alias = name === helperName ? undefined : name;
+              const tslibImport = createTslibImport(helperName, alias, useRequire);
               tslibImports.push(tslibImport);
 
               return undefined;
@@ -66,6 +73,7 @@ export function getImportTslibTransformer(): ts.TransformerFactory<ts.SourceFile
 
 function createTslibImport(
   name: string,
+  aliases?: string,
   useRequire = false,
 ): ts.VariableStatement | ts.ImportDeclaration {
   if (useRequire) {
@@ -75,14 +83,15 @@ function createTslibImport(
     const pureRequireCall = ts.addSyntheticLeadingComment(
       requireCall, ts.SyntaxKind.MultiLineCommentTrivia, '@__PURE__', false);
     const helperAccess = ts.createPropertyAccess(pureRequireCall, name);
-    const variableDeclaration = ts.createVariableDeclaration(name, undefined, helperAccess);
+    const variableDeclaration = ts.createVariableDeclaration(aliases || name, undefined, helperAccess);
     const variableStatement = ts.createVariableStatement(undefined, [variableDeclaration]);
 
     return variableStatement;
   } else {
     // Use `import { __helper } from "tslib"`.
-    const namedImports = ts.createNamedImports([ts.createImportSpecifier(undefined,
-      ts.createIdentifier(name))]);
+    const namedImports = ts.createNamedImports([
+      ts.createImportSpecifier(aliases ? ts.createIdentifier(name) : undefined, ts.createIdentifier(aliases || name)),
+    ]);
     const importClause = ts.createImportClause(undefined, namedImports);
     const newNode = ts.createImportDeclaration(undefined, undefined, importClause,
       ts.createLiteral('tslib'));
diff --git a/packages/angular_devkit/build_optimizer/src/transforms/import-tslib_spec.ts b/packages/angular_devkit/build_optimizer/src/transforms/import-tslib_spec.ts
index 5dfb65fae2f2..20bc023a2d97 100644
--- a/packages/angular_devkit/build_optimizer/src/transforms/import-tslib_spec.ts
+++ b/packages/angular_devkit/build_optimizer/src/transforms/import-tslib_spec.ts
@@ -68,6 +68,60 @@ describe('import-tslib', () => {
     expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
   });
 
+  it('replaces multiple __decorate', () => {
+    // tslint:disable:max-line-length
+    const input = tags.stripIndent`
+      var __decorate$1 = (this && this.__decorate) || function (decorators, target, key, desc) {
+          var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+          if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+          else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+          return c > 3 && r && Object.defineProperty(target, key, r), r;
+      };
+      var __decorate$2 = (this && this.__decorate) || function (decorators, target, key, desc) {
+        var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+        if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+        else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+        return c > 3 && r && Object.defineProperty(target, key, r), r;
+    };
+    `;
+    const output = tags.stripIndent`
+      import { __decorate as __decorate$1 } from "tslib";
+      import { __decorate as __decorate$2 } from "tslib";
+    `;
+
+    expect(testImportTslib(input)).toBeTruthy();
+    expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
+  });
+
+  it('replaces multiple __decorate in CJS modules', () => {
+    // tslint:disable:max-line-length
+    const input = tags.stripIndent`
+      var __decorate$1 = (this && this.__decorate) || function (decorators, target, key, desc) {
+          var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+          if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+          else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+          return c > 3 && r && Object.defineProperty(target, key, r), r;
+      };
+      var __decorate$2 = (this && this.__decorate) || function (decorators, target, key, desc) {
+        var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
+        if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
+        else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
+        return c > 3 && r && Object.defineProperty(target, key, r), r;
+      };
+
+      exports.meaning = 42;
+    `;
+    const output = tags.stripIndent`
+      var __decorate$1 = /*@__PURE__*/ require("tslib").__decorate;
+      var __decorate$2 = /*@__PURE__*/ require("tslib").__decorate;
+
+      exports.meaning = 42;
+    `;
+
+    expect(testImportTslib(input)).toBeTruthy();
+    expect(tags.oneLine`${transform(input)}`).toEqual(tags.oneLine`${output}`);
+  });
+
   it('replaces __metadata', () => {
     const input = tags.stripIndent`
       var __metadata = (this && this.__metadata) || function (k, v) {