Merge pull request #15357 from Microsoft/es2015-transform-accessors-containing-captured-this

es2015 transform covers accessors that contain captured this

Author: sandersn

src/compiler/transformers/es2015.ts

@@ -3180,7 +3180,20 @@ namespace ts {
             const savedConvertedLoopState = convertedLoopState;
             convertedLoopState = undefined;
             const ancestorFacts = enterSubtree(HierarchyFacts.FunctionExcludes, HierarchyFacts.FunctionIncludes);
-            const updated = visitEachChild(node, visitor, context);
+            let updated: AccessorDeclaration;
+            if (node.transformFlags & TransformFlags.ContainsCapturedLexicalThis) {
+                const parameters = visitParameterList(node.parameters, visitor, context);
+                const body = transformFunctionBody(node);
+                if (node.kind === SyntaxKind.GetAccessor) {
+                    updated = updateGetAccessor(node, node.decorators, node.modifiers, node.name, parameters, node.type, body);
+                }
+                else {
+                    updated = updateSetAccessor(node, node.decorators, node.modifiers, node.name, parameters, body);
+                }
+            }
+            else {
+                updated = visitEachChild(node, visitor, context);
+            }
             exitSubtree(ancestorFacts, HierarchyFacts.PropagateNewTargetMask, HierarchyFacts.None);
             convertedLoopState = savedConvertedLoopState;
             return updated;

tests/baselines/reference/emitThisInObjectLiteralGetter.js

@@ -0,0 +1,15 @@
+//// [emitThisInObjectLiteralGetter.ts]
+const example = {
+    get foo() {
+        return item => this.bar(item);
+    }
+};
+
+
+//// [emitThisInObjectLiteralGetter.js]
+var example = {
+    get foo() {
+        var _this = this;
+        return function (item) { return _this.bar(item); };
+    }
+};

tests/baselines/reference/emitThisInObjectLiteralGetter.symbols

@@ -0,0 +1,13 @@
+=== tests/cases/compiler/emitThisInObjectLiteralGetter.ts ===
+const example = {
+>example : Symbol(example, Decl(emitThisInObjectLiteralGetter.ts, 0, 5))
+
+    get foo() {
+>foo : Symbol(foo, Decl(emitThisInObjectLiteralGetter.ts, 0, 17))
+
+        return item => this.bar(item);
+>item : Symbol(item, Decl(emitThisInObjectLiteralGetter.ts, 2, 14))
+>item : Symbol(item, Decl(emitThisInObjectLiteralGetter.ts, 2, 14))
+    }
+};
+

tests/baselines/reference/emitThisInObjectLiteralGetter.types

@@ -0,0 +1,19 @@
+=== tests/cases/compiler/emitThisInObjectLiteralGetter.ts ===
+const example = {
+>example : { readonly foo: (item: any) => any; }
+>{    get foo() {        return item => this.bar(item);    }} : { readonly foo: (item: any) => any; }
+
+    get foo() {
+>foo : (item: any) => any
+
+        return item => this.bar(item);
+>item => this.bar(item) : (item: any) => any
+>item : any
+>this.bar(item) : any
+>this.bar : any
+>this : any
+>bar : any
+>item : any
+    }
+};
+

tests/cases/compiler/emitThisInObjectLiteralGetter.ts

@@ -0,0 +1,6 @@
+// @target: es5
+const example = {
+    get foo() {
+        return item => this.bar(item);
+    }
+};