Merge pull request microsoft#7952 from Microsoft/objectAssignPoly

Use an emit helper (or Object.assign) for JsxSpreadAttributes

Author: DanielRosenwasser

src/compiler/binder.ts

@@ -122,6 +122,7 @@ namespace ts {
  let hasAsyncFunctions: boolean;
  let hasDecorators: boolean;
  let hasParameterDecorators: boolean;
+ let hasJsxSpreadAttribute: boolean;
 
  // If this file is an external module, then it is automatically in strict-mode according to
  // ES6. If it is not an external module, then we'll determine if it is in strict mode or
@@ -161,6 +162,7 @@ namespace ts {
  hasAsyncFunctions = false;
  hasDecorators = false;
  hasParameterDecorators = false;
+ hasJsxSpreadAttribute = false;
  }
 
  return bindSourceFile;
@@ -498,6 +500,9 @@ namespace ts {
  if (hasAsyncFunctions) {
  flags |= NodeFlags.HasAsyncFunctions;
  }
+ if (hasJsxSpreadAttribute) {
+ flags |= NodeFlags.HasJsxSpreadAttribute;
+ }
  }
 
  node.flags = flags;
@@ -1298,6 +1303,10 @@ namespace ts {
  case SyntaxKind.EnumMember:
  return bindPropertyOrMethodOrAccessor(<Declaration>node, SymbolFlags.EnumMember, SymbolFlags.EnumMemberExcludes);
 
+ case SyntaxKind.JsxSpreadAttribute:
+ hasJsxSpreadAttribute = true;
+ return;
+
  case SyntaxKind.CallSignature:
  case SyntaxKind.ConstructSignature:
  case SyntaxKind.IndexSignature:

src/compiler/emitter.ts

@@ -345,6 +345,16 @@ var __extends = (this && this.__extends) || function (d, b) {
  d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
 };`;
 
+ const assignHelper = `
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};`;
+
  // emit output for the __decorate helper function
  const decorateHelper = `
 var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
@@ -542,6 +552,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
  let convertedLoopState: ConvertedLoopState;
 
  let extendsEmitted: boolean;
+ let assignEmitted: boolean;
  let decorateEmitted: boolean;
  let paramEmitted: boolean;
  let awaiterEmitted: boolean;
@@ -625,6 +636,7 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
  decorateEmitted = false;
  paramEmitted = false;
  awaiterEmitted = false;
+ assignEmitted = false;
  tempFlags = 0;
  tempVariables = undefined;
  tempParameters = undefined;
@@ -1261,11 +1273,10 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
  }
  else {
  // Either emit one big object literal (no spread attribs), or
- // a call to React.__spread
+ // a call to the __assign helper
  const attrs = openingNode.attributes;
  if (forEach(attrs, attr => attr.kind === SyntaxKind.JsxSpreadAttribute)) {
- emitExpressionIdentifier(syntheticReactRef);
- write(".__spread(");
+ write("__assign(");
 
  let haveOpenedObjectLiteral = false;
  for (let i = 0; i < attrs.length; i++) {
@@ -7704,11 +7715,16 @@ const _super = (function (geti, seti) {
  if (!compilerOptions.noEmitHelpers) {
  // Only Emit __extends function when target ES5.
  // For target ES6 and above, we can emit classDeclaration as is.
- if ((languageVersion < ScriptTarget.ES6) && (!extendsEmitted && node.flags & NodeFlags.HasClassExtends)) {
+ if (languageVersion < ScriptTarget.ES6 && !extendsEmitted && node.flags & NodeFlags.HasClassExtends) {
  writeLines(extendsHelper);
  extendsEmitted = true;
  }
 
+ if (compilerOptions.jsx !== JsxEmit.Preserve && !assignEmitted && (node.flags & NodeFlags.HasJsxSpreadAttribute)) {
+ writeLines(assignHelper);
+ assignEmitted = true;
+ }
+
  if (!decorateEmitted && node.flags & NodeFlags.HasDecorators) {
  writeLines(decorateHelper);
  if (compilerOptions.emitDecoratorMetadata) {

src/compiler/types.ts

@@ -405,6 +405,7 @@ namespace ts {
  JavaScriptFile = 1 << 27, // If node was parsed in a JavaScript
  ThisNodeOrAnySubNodesHasError = 1 << 28, // If this node or any of its children had an error
  HasAggregatedChildData = 1 << 29, // If we've computed data from children and cached it in this node
+ HasJsxSpreadAttribute = 1 << 30,
 
  Modifier = Export | Ambient | Public | Private | Protected | Static | Abstract | Default | Async,
  AccessibilityModifier = Public | Private | Protected,

tests/baselines/reference/reactNamespaceJSXEmit.js

@@ -13,8 +13,16 @@ declare var x: any;
 
 
 //// [reactNamespaceJSXEmit.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};
 myReactLib.createElement("foo", {data: true});
 myReactLib.createElement(Bar, {x: x});
 myReactLib.createElement("x-component", null);
-myReactLib.createElement(Bar, myReactLib.__spread({}, x));
-myReactLib.createElement(Bar, myReactLib.__spread({}, x, {y: 2}));
+myReactLib.createElement(Bar, __assign({}, x));
+myReactLib.createElement(Bar, __assign({}, x, {y: 2}));

tests/baselines/reference/tsxExternalModuleEmit2.js

@@ -19,8 +19,16 @@ declare var Foo, React;
 
 //// [app.js]
 "use strict";
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};
 var mod_1 = require('mod');
 // Should see mod_1['default'] in emit here
 React.createElement(Foo, {handler: mod_1["default"]});
 // Should see mod_1['default'] in emit here
-React.createElement(Foo, React.__spread({}, mod_1["default"]));
+React.createElement(Foo, __assign({}, mod_1["default"]));

tests/baselines/reference/tsxReactEmit2.js

@@ -16,9 +16,17 @@ var spreads5 = <div x={p2} {...p1} y={p3}>{p2}</div>;
 
 
 //// [file.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};
 var p1, p2, p3;
-var spreads1 = React.createElement("div", React.__spread({}, p1), p2);
-var spreads2 = React.createElement("div", React.__spread({}, p1), p2);
-var spreads3 = React.createElement("div", React.__spread({x: p3}, p1), p2);
-var spreads4 = React.createElement("div", React.__spread({}, p1, {x: p3}), p2);
-var spreads5 = React.createElement("div", React.__spread({x: p2}, p1, {y: p3}), p2);
+var spreads1 = React.createElement("div", __assign({}, p1), p2);
+var spreads2 = React.createElement("div", __assign({}, p1), p2);
+var spreads3 = React.createElement("div", __assign({x: p3}, p1), p2);
+var spreads4 = React.createElement("div", __assign({}, p1, {x: p3}), p2);
+var spreads5 = React.createElement("div", __assign({x: p2}, p1, {y: p3}), p2);

tests/baselines/reference/tsxReactEmit4.js

@@ -18,7 +18,15 @@ var openClosed1 = <div>
 var spread1 = <div {...p} x={0} />;
 
 //// [file.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};
 var p;
 var openClosed1 = React.createElement("div", null, blah);
 // Should emit React.__spread({}, p, {x: 0})
-var spread1 = React.createElement("div", React.__spread({}, p, {x: 0}));
+var spread1 = React.createElement("div", __assign({}, p, {x: 0}));

tests/baselines/reference/tsxReactEmit5.js

@@ -23,8 +23,16 @@ var spread1 = <div x='' {...foo} y='' />;
 //// [file.js]
 //// [react-consumer.js]
 "use strict";
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};
 var test_1 = require("./test");
 // Should emit test_1.React.createElement
 // and React.__spread
 var foo;
-var spread1 = test_1.React.createElement("div", test_1.React.__spread({x: ''}, foo, {y: ''}));
+var spread1 = test_1.React.createElement("div", __assign({x: ''}, foo, {y: ''}));

tests/baselines/reference/tsxReactEmit6.js

@@ -28,6 +28,14 @@ namespace M {
 
 //// [file.js]
 //// [react-consumer.js]
+var __assign = (this && this.__assign) || Object.assign || function(t) {
+ for (var s, i = 1, n = arguments.length; i < n; i++) {
+ s = arguments[i];
+ for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
+ t[p] = s[p];
+ }
+ return t;
+};
 var M;
 (function (M) {
 })(M || (M = {}));
@@ -36,7 +44,7 @@ var M;
  // Should emit M.React.createElement
  // and M.React.__spread
  var foo;
- var spread1 = M.React.createElement("div", M.React.__spread({x: ''}, foo, {y: ''}));
+ var spread1 = M.React.createElement("div", __assign({x: ''}, foo, {y: ''}));
  // Quotes
  var x = M.React.createElement("div", null, "This \"quote\" thing");
 })(M || (M = {}));