Merge pull request microsoft#3524 from Microsoft/extendsNull

Support null in __extends helper

Author: ahejlsberg

src/compiler/emitter.ts

@@ -21,8 +21,7 @@ namespace ts {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };`;
 
         // emit output for the __decorate helper function

tests/baselines/reference/ExportClassWithAccessibleTypesInTypeParameterConstraintsClassHeritageListMemberTypeAnnotations.js

@@ -24,8 +24,7 @@ module A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A;
 (function (A) {

tests/baselines/reference/ExportClassWithInaccessibleTypeInTypeParameterConstraint.js

@@ -28,8 +28,7 @@ module A {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A;
 (function (A) {

tests/baselines/reference/accessOverriddenBaseClassMember1.js

@@ -19,8 +19,7 @@ class ColoredPoint extends Point {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Point = (function () {
     function Point(x, y) {

tests/baselines/reference/accessors_spec_section-4.5_inference.js

@@ -28,8 +28,7 @@ class LanguageSpec_section_4_5_inference {
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var A = (function () {
     function A() {

tests/baselines/reference/aliasUsageInAccessorsOfClass.js

@@ -38,8 +38,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsage1_backbone");
 var VisualizationModel = (function (_super) {

tests/baselines/reference/aliasUsageInArray.js

@@ -32,8 +32,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInArray_backbone");
 var VisualizationModel = (function (_super) {

tests/baselines/reference/aliasUsageInFunctionExpression.js

@@ -31,8 +31,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInFunctionExpression_backbone");
 var VisualizationModel = (function (_super) {

tests/baselines/reference/aliasUsageInGenericFunction.js

@@ -35,8 +35,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInGenericFunction_backbone");
 var VisualizationModel = (function (_super) {

tests/baselines/reference/aliasUsageInIndexerOfClass.js

@@ -37,8 +37,7 @@ exports.Model = Model;
 var __extends = (this && this.__extends) || function (d, b) {
     for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
     function __() { this.constructor = d; }
-    __.prototype = b.prototype;
-    d.prototype = new __();
+    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };
 var Backbone = require("aliasUsageInIndexerOfClass_backbone");
 var VisualizationModel = (function (_super) {