Transform arrow function in variable declaration to named function

src/compiler/transformers/es2015.ts

@@ -1679,17 +1679,18 @@ namespace ts {
          *
          * @param node An ArrowFunction node.
          */
-        function visitArrowFunction(node: ArrowFunction) {
+        function visitArrowFunction(node: ArrowFunction, functionName?: Identifier) {
             if (node.transformFlags & TransformFlags.ContainsLexicalThis) {
                 enableSubstitutionsForCapturedThis();
             }
             const savedConvertedLoopState = convertedLoopState;
             convertedLoopState = undefined;
             const ancestorFacts = enterSubtree(HierarchyFacts.ArrowFunctionExcludes, HierarchyFacts.ArrowFunctionIncludes);
+
             const func = createFunctionExpression(
                 /*modifiers*/ undefined,
                 /*asteriskToken*/ undefined,
-                /*name*/ undefined,
+                /*name*/ functionName,
                 /*typeParameters*/ undefined,
                 visitParameterList(node.parameters, visitor, context),
                 /*type*/ undefined,
@@ -1708,7 +1709,7 @@ namespace ts {
          *
          * @param node a FunctionExpression node.
          */
-        function visitFunctionExpression(node: FunctionExpression): Expression {
+        function visitFunctionExpression(node: FunctionExpression, functionName?: Identifier): Expression {
             const ancestorFacts = getEmitFlags(node) & EmitFlags.AsyncFunctionBody
                 ? enterSubtree(HierarchyFacts.AsyncFunctionBodyExcludes, HierarchyFacts.AsyncFunctionBodyIncludes)
                 : enterSubtree(HierarchyFacts.FunctionExcludes, HierarchyFacts.FunctionIncludes);
@@ -1721,7 +1722,7 @@ namespace ts {
                 : visitFunctionBodyDownLevel(node);
             const name = hierarchyFacts & HierarchyFacts.NewTarget
                 ? getLocalName(node)
-                : node.name;
+                : (functionName && !node.name) ? functionName : node.name;
 
             exitSubtree(ancestorFacts, HierarchyFacts.PropagateNewTargetMask, HierarchyFacts.None);
             convertedLoopState = savedConvertedLoopState;
@@ -2164,7 +2165,24 @@ namespace ts {
         function visitVariableDeclaration(node: VariableDeclaration): VisitResult<VariableDeclaration> {
             const ancestorFacts = enterSubtree(HierarchyFacts.ExportedVariableStatement, HierarchyFacts.None);
             let updated: VisitResult<VariableDeclaration>;
-            if (isBindingPattern(node.name)) {
+
+            if (isArrowFunction(node.initializer)) {
+                const clonedNode = getMutableClone(node);
+                const name = (clonedNode.name && (<Identifier>clonedNode.name).text) ? createIdentifier((<Identifier>clonedNode.name).text) : undefined;
+                if (name) {
+                    name.parent = clonedNode.initializer;
+                }
+                clonedNode.initializer = visitArrowFunction((<ArrowFunction>node.initializer), name);
+                updated = clonedNode;
+            } else if (isFunctionExpression(node.initializer)) {
+                const clonedNode = getMutableClone(node);
+                const name = (clonedNode.name && (<Identifier>clonedNode.name).text) ? createIdentifier((<Identifier>clonedNode.name).text) : undefined;
+                if (name) {
+                    name.parent = clonedNode.initializer;
+                }
+                clonedNode.initializer = visitFunctionExpression(<FunctionExpression>node.initializer, name);
+                updated = clonedNode;
+            } else if (isBindingPattern(node.name)) {
                 updated = flattenDestructuringBinding(
                     node,
                     visitor,
@@ -2173,8 +2191,7 @@ namespace ts {
                     /*value*/ undefined,
                     (ancestorFacts & HierarchyFacts.ExportedVariableStatement) !== 0
                 );
-            }
-            else {
+            } else {
                 updated = visitEachChild(node, visitor, context);
             }
 

src/compiler/utilities.ts

@@ -3764,6 +3764,22 @@ namespace ts {
             || kind === SyntaxKind.OmittedExpression;
     }
 
+    export function isArrowFunction(node?: Node): node is ArrowFunction {
+        if (node) {
+            return node.kind === SyntaxKind.ArrowFunction;
+        }
+
+        return false;
+    }
+
+    export function isFunctionExpression(node?: Node): node is FunctionExpression {
+        if (node) {
+            return node.kind === SyntaxKind.FunctionExpression;
+        }
+
+        return false;
+    }
+
 
     /**
      * Determines whether the BindingOrAssignmentElement is a BindingElement-like declaration

tests/baselines/reference/ArrowFunction1.js

@@ -4,5 +4,5 @@ var v = (a: ) => {
 };
 
 //// [ArrowFunction1.js]
-var v = function (a) {
+var v = function v(a) {
 };

tests/baselines/reference/ArrowFunction3.js

@@ -4,5 +4,5 @@ var v = (a): => {
 };
 
 //// [ArrowFunction3.js]
-var v = function (a) {
+var v = function v(a) {
 };

tests/baselines/reference/ArrowFunction4.js

@@ -4,5 +4,5 @@ var v = (a, b) => {
 };
 
 //// [ArrowFunction4.js]
-var v = function (a, b) {
+var v = function v(a, b) {
 };

tests/baselines/reference/ArrowFunctionExpression1.js

@@ -2,4 +2,4 @@
 var v = (public x: string) => { };
 
 //// [ArrowFunctionExpression1.js]
-var v = function (x) { };
+var v = function v(x) { };

tests/baselines/reference/ClassDeclaration26.js

@@ -12,4 +12,4 @@ var C = (function () {
     }
     return C;
 }());
-var constructor = function () { };
+var constructor = function constructor() { };

tests/baselines/reference/aliasUsageInFunctionExpression.js

@@ -55,5 +55,5 @@ exports.VisualizationModel = VisualizationModel;
 "use strict";
 exports.__esModule = true;
 var moduleA = require("./aliasUsageInFunctionExpression_moduleA");
-var f = function (x) { return x; };
+var f = function f(x) { return x; };
 f = function (x) { return moduleA; };

tests/baselines/reference/aliasUsedAsNameValue.js

@@ -33,7 +33,7 @@ exports.__esModule = true;
 ///<reference path='aliasUsedAsNameValue_1.ts' />
 var mod = require("./aliasUsedAsNameValue_0");
 var b = require("./aliasUsedAsNameValue_1");
-exports.a = function () {
+exports.a = function a() {
     //var x = mod.id; // TODO needed hack that mod is loaded
     b.b(mod);
 };

tests/baselines/reference/ambiguousGenericAssertion1.js

@@ -7,7 +7,7 @@ var r3 = <<T>(x: T) => T>f; // ambiguous, appears to the parser as a << operatio
 
 //// [ambiguousGenericAssertion1.js]
 function f(x) { return null; }
-var r = function (x) { return x; };
+var r = function r(x) { return x; };
 var r2 = f; // valid
 var r3 =  << T > (x), T;
 T > f; // ambiguous, appears to the parser as a << operation

tests/baselines/reference/arrayAssignmentTest1.js

@@ -134,7 +134,7 @@ var i1 = c1;
 var c2 = new C2();
 var c3 = new C3();
 var o1 = { one: 1 };
-var f1 = function () { return new C1(); };
+var f1 = function f1() { return new C1(); };
 var arr_any = [];
 var arr_i1 = [];
 var arr_c1 = [];

tests/baselines/reference/arrayAssignmentTest2.js

@@ -108,7 +108,7 @@ var i1 = c1;
 var c2 = new C2();
 var c3 = new C3();
 var o1 = { one: 1 };
-var f1 = function () { return new C1(); };
+var f1 = function f1() { return new C1(); };
 var arr_any = [];
 var arr_i1 = [];
 var arr_c1 = [];

tests/baselines/reference/arrowFunctionContexts.js

@@ -109,7 +109,7 @@ var __extends = (this && this.__extends) || (function () {
 var _this = this;
 // Arrow function used in with statement
 with (window) {
-    var p = function () { return _this; };
+    var p = function p() { return _this; };
 }
 // Arrow function as argument to super call
 var Base = (function () {
@@ -128,7 +128,7 @@ var Derived = (function (_super) {
 // Arrow function as function argument
 window.setTimeout(function () { return null; }, 100);
 // Arrow function as value in array literal
-var obj = function (n) { return ''; };
+var obj = function obj(n) { return ''; };
 var obj; // OK
 var arr = [function (n) { return ''; }];
 var arr; // Incorrect error here (bug 829597)
@@ -143,15 +143,15 @@ var E;
 var M;
 (function (M) {
     M.a = function (s) { return ''; };
-    var b = function (s) { return s; };
+    var b = function b(s) { return s; };
 })(M || (M = {}));
 // Repeat above for module members that are functions? (necessary to redo all of them?)
 var M2;
 (function (M2) {
     var _this = this;
     // Arrow function used in with statement
     with (window) {
-        var p = function () { return _this; };
+        var p = function p() { return _this; };
     }
     // Arrow function as argument to super call
     var Base = (function () {
@@ -170,7 +170,7 @@ var M2;
     // Arrow function as function argument
     window.setTimeout(function () { return null; }, 100);
     // Arrow function as value in array literal
-    var obj = function (n) { return ''; };
+    var obj = function obj(n) { return ''; };
     var obj; // OK
     var arr = [function (n) { return ''; }];
     var arr; // Incorrect error here (bug 829597)
@@ -185,13 +185,13 @@ var M2;
     var M;
     (function (M) {
         M.a = function (s) { return ''; };
-        var b = function (s) { return s; };
+        var b = function b(s) { return s; };
     })(M || (M = {}));
 })(M2 || (M2 = {}));
 // <Identifier>(ParamList) => { ... } is a generic arrow function
-var generic1 = function (n) { return [n]; };
+var generic1 = function generic1(n) { return [n]; };
 var generic1; // Incorrect error, Bug 829597
-var generic2 = function (n) { return [n]; };
+var generic2 = function generic2(n) { return [n]; };
 var generic2;
 // <Identifier> ((ParamList) => { ... } ) is a type assertion to an arrow function
 var asserted1 = (function (n) { return [n]; });

tests/baselines/reference/arrowFunctionExpressions.js

@@ -101,45 +101,45 @@ function tryCatchFn() {
 
 //// [arrowFunctionExpressions.js]
 // ArrowFormalParameters => AssignmentExpression is equivalent to ArrowFormalParameters => { return AssignmentExpression; }
-var a = function (p) { return p.length; };
-var a = function (p) { return p.length; };
+var a = function a(p) { return p.length; };
+var a = function a(p) { return p.length; };
 // Identifier => Block is equivalent to(Identifier) => Block
-var b = function (j) { return 0; };
-var b = function (j) { return 0; };
+var b = function b(j) { return 0; };
+var b = function b(j) { return 0; };
 // Identifier => AssignmentExpression is equivalent to(Identifier) => AssignmentExpression
 var c;
-var d = function (n) { return c = n; };
-var d = function (n) { return c = n; };
+var d = function d(n) { return c = n; };
+var d = function d(n) { return c = n; };
 var d;
 // Binding patterns in arrow functions
-var p1 = function (_a) {
+var p1 = function p1(_a) {
     var a = _a[0];
 };
-var p2 = function (_a) {
+var p2 = function p2(_a) {
     var a = _a.slice(0);
 };
-var p3 = function (_a) {
+var p3 = function p3(_a) {
     var a = _a[1];
 };
-var p4 = function (_a) {
+var p4 = function p4(_a) {
     var a = _a.slice(1);
 };
-var p5 = function (_a) {
+var p5 = function p5(_a) {
     var _b = _a[0], a = _b === void 0 ? 1 : _b;
 };
-var p6 = function (_a) {
+var p6 = function p6(_a) {
     var a = _a.a;
 };
-var p7 = function (_a) {
+var p7 = function p7(_a) {
     var b = _a.a.b;
 };
-var p8 = function (_a) {
+var p8 = function p8(_a) {
     var _b = _a.a, a = _b === void 0 ? 1 : _b;
 };
-var p9 = function (_a) {
+var p9 = function p9(_a) {
     var _b = _a.a, _c = (_b === void 0 ? { b: 1 } : _b).b, b = _c === void 0 ? 1 : _c;
 };
-var p10 = function (_a) {
+var p10 = function p10(_a) {
     var _b = _a[0], value = _b.value, done = _b.done;
 };
 // Arrow function used in class member initializer
@@ -152,35 +152,35 @@ var MyClass = (function () {
     }
     MyClass.prototype.fn = function () {
         var _this = this;
-        var m = function (n) { return n + 1; };
-        var p = function (n) { return n && _this; };
+        var m = function m(n) { return n + 1; };
+        var p = function p(n) { return n && _this; };
     };
     return MyClass;
 }());
 // Arrow function used in arrow function
-var arrrr = function () { return function (m) { return function () { return function (n) { return m + n; }; }; }; };
+var arrrr = function arrrr() { return function (m) { return function () { return function (n) { return m + n; }; }; }; };
 var e = arrrr()(3)()(4);
 var e;
 // Arrow function used in arrow function used in function
 function someFn() {
-    var arr = function (n) { return function (p) { return p * n; }; };
+    var arr = function arr(n) { return function (p) { return p * n; }; };
     arr(3)(4).toExponential();
 }
 // Arrow function used in function
 function someOtherFn() {
-    var arr = function (n) { return '' + n; };
+    var arr = function arr(n) { return '' + n; };
     arr(4).charAt(0);
 }
 // Arrow function used in nested function in function
 function outerFn() {
     function innerFn() {
-        var arrowFn = function () { };
+        var arrowFn = function arrowFn() { };
         var p = arrowFn();
         var p;
     }
 }
 // Arrow function used in nested function in arrow function
-var f = function (n) {
+var f = function f(n) {
     function fn(x) {
         return function () { return n + x; };
     }
@@ -190,7 +190,7 @@ var g = f('')();
 var g;
 // Arrow function used in nested function in arrow function in nested function
 function someOuterFn() {
-    var arr = function (n) {
+    var arr = function arr(n) {
         function innerFn() {
             return function () { return n.length; };
         }
@@ -204,12 +204,12 @@ h.toExponential();
 function tryCatchFn() {
     var _this = this;
     try {
-        var x = function () { return _this; };
+        var x = function x() { return _this; };
     }
     catch (e) {
-        var t = function () { return e + _this; };
+        var t = function t() { return e + _this; };
     }
     finally {
-        var m = function () { return _this + ''; };
+        var m = function m() { return _this + ''; };
     }
 }

tests/baselines/reference/arrowFunctionMissingCurlyWithSemicolon.js

@@ -6,6 +6,6 @@ var square = (x: number) => x * x;
 
 //// [arrowFunctionMissingCurlyWithSemicolon.js]
 // Should error at semicolon.
-var f = function () { return ; };
+var f = function f() { return ; };
 var b = 1 * 2 * 3 * 4;
-var square = function (x) { return x * x; };
+var square = function square(x) { return x * x; };

tests/baselines/reference/arrowFunctionWithObjectLiteralBody1.js

@@ -2,4 +2,4 @@
 var v = a => <any>{}
 
 //// [arrowFunctionWithObjectLiteralBody1.js]
-var v = function (a) { return ({}); };
+var v = function v(a) { return ({}); };

tests/baselines/reference/arrowFunctionWithObjectLiteralBody2.js

@@ -2,4 +2,4 @@
 var v = a => <any><any>{}
 
 //// [arrowFunctionWithObjectLiteralBody2.js]
-var v = function (a) { return ({}); };
+var v = function v(a) { return ({}); };

tests/baselines/reference/arrowFunctionWithObjectLiteralBody5.js

@@ -8,7 +8,7 @@ var c = () => ({ name: "foo", message: "bar" });
 var d = () => ((<Error>({ name: "foo", message: "bar" })));
 
 //// [arrowFunctionWithObjectLiteralBody5.js]
-var a = function () { return ({ name: "foo", message: "bar" }); };
-var b = function () { return ({ name: "foo", message: "bar" }); };
-var c = function () { return ({ name: "foo", message: "bar" }); };
-var d = function () { return (({ name: "foo", message: "bar" })); };
+var a = function a() { return ({ name: "foo", message: "bar" }); };
+var b = function b() { return ({ name: "foo", message: "bar" }); };
+var c = function c() { return ({ name: "foo", message: "bar" }); };
+var d = function d() { return (({ name: "foo", message: "bar" })); };