Add spread syntax to JsxExpression

src/compiler/checker.ts

@@ -12187,7 +12187,11 @@ namespace ts {
 
         function checkJsxExpression(node: JsxExpression) {
             if (node.expression) {
-                return checkExpression(node.expression);
+                const type = checkExpression(node.expression);
+                if (node.dotDotDotToken && type !== anyType && !isArrayType(type)) {
+                    error(node, Diagnostics.JSX_spread_child_must_be_an_array_type, node.toString(), typeToString(type));
+                }
+                return type;
             }
             else {
                 return unknownType;

src/compiler/diagnosticMessages.json

@@ -1811,6 +1811,10 @@
         "category": "Error",
         "code": 2608
     },
+    "JSX spread child must be an array type.": {
+        "category": "Error",
+        "code": 2609
+    },
     "Cannot emit namespaced JSX elements in React": {
         "category": "Error",
         "code": 2650

src/compiler/emitter.ts

@@ -1854,6 +1854,9 @@ namespace ts {
         function emitJsxExpression(node: JsxExpression) {
             if (node.expression) {
                 write("{");
+                if (node.dotDotDotToken) {
+                    write("...");
+                }
                 emitExpression(node.expression);
                 write("}");
             }

src/compiler/factory.ts

@@ -1317,15 +1317,16 @@ namespace ts {
         return node;
     }
 
-    export function createJsxExpression(expression: Expression, location?: TextRange) {
+    export function createJsxExpression(expression: Expression, dotDotDotToken: Token<SyntaxKind.DotDotDotToken>, location?: TextRange) {
         const node = <JsxExpression>createNode(SyntaxKind.JsxExpression, location);
+        node.dotDotDotToken = dotDotDotToken;
         node.expression = expression;
         return node;
     }
 
     export function updateJsxExpression(node: JsxExpression, expression: Expression) {
         if (node.expression !== expression) {
-            return updateNode(createJsxExpression(expression, node), node);
+            return updateNode(createJsxExpression(expression, node.dotDotDotToken, node), node);
         }
         return node;
     }

src/compiler/parser.ts

@@ -373,7 +373,8 @@ namespace ts {
             case SyntaxKind.JsxSpreadAttribute:
                 return visitNode(cbNode, (<JsxSpreadAttribute>node).expression);
             case SyntaxKind.JsxExpression:
-                return visitNode(cbNode, (<JsxExpression>node).expression);
+                return visitNode(cbNode, (node as JsxExpression).dotDotDotToken) ||
+                    visitNode(cbNode, (node as JsxExpression).expression);
             case SyntaxKind.JsxClosingElement:
                 return visitNode(cbNode, (<JsxClosingElement>node).tagName);
 
@@ -3914,6 +3915,7 @@ namespace ts {
 
             parseExpected(SyntaxKind.OpenBraceToken);
             if (token() !== SyntaxKind.CloseBraceToken) {
+                node.dotDotDotToken = parseOptionalToken(SyntaxKind.DotDotDotToken);
                 node.expression = parseAssignmentExpressionOrHigher();
             }
             if (inExpressionContext) {

src/compiler/types.ts

@@ -1492,6 +1492,7 @@ namespace ts {
 
     export interface JsxExpression extends Expression {
         kind: SyntaxKind.JsxExpression;
+        dotDotDotToken?: Token<SyntaxKind.DotDotDotToken>;
         expression?: Expression;
     }
 

tests/baselines/reference/tsxSpreadChildren.js

@@ -0,0 +1,41 @@
+//// [tsxSpreadChildren.tsx]
+
+declare module JSX {
+	interface Element { }
+	interface IntrinsicElements {
+		[s: string]: any;
+	}
+}
+declare var React: any;
+
+interface TodoProp {
+    id: number;
+    todo: string;
+}
+interface TodoListProps {
+    todos: TodoProp[];
+}
+function Todo(prop: { key: number, todo: string }) {
+    return <div>{prop.key.toString() + prop.todo}</div>;
+}
+function TodoList({ todos }: TodoListProps) {
+    return <div>
+        {...todos.map(todo => <Todo key={todo.id} todo={todo.todo}/>)}
+    </div>;
+}
+let x: TodoListProps;
+    <TodoList {...x}/>
+
+
+//// [tsxSpreadChildren.jsx]
+function Todo(prop) {
+    return <div>{prop.key.toString() + prop.todo}</div>;
+}
+function TodoList(_a) {
+    var todos = _a.todos;
+    return <div>
+        {...todos.map(function (todo) { return <Todo key={todo.id} todo={todo.todo}/>; })}
+    </div>;
+}
+var x;
+<TodoList {...x}/>;

tests/baselines/reference/tsxSpreadChildren.symbols

@@ -0,0 +1,86 @@
+=== tests/cases/conformance/jsx/tsxSpreadChildren.tsx ===
+
+declare module JSX {
+>JSX : Symbol(JSX, Decl(tsxSpreadChildren.tsx, 0, 0))
+
+	interface Element { }
+>Element : Symbol(Element, Decl(tsxSpreadChildren.tsx, 1, 20))
+
+	interface IntrinsicElements {
+>IntrinsicElements : Symbol(IntrinsicElements, Decl(tsxSpreadChildren.tsx, 2, 22))
+
+		[s: string]: any;
+>s : Symbol(s, Decl(tsxSpreadChildren.tsx, 4, 3))
+	}
+}
+declare var React: any;
+>React : Symbol(React, Decl(tsxSpreadChildren.tsx, 7, 11))
+
+interface TodoProp {
+>TodoProp : Symbol(TodoProp, Decl(tsxSpreadChildren.tsx, 7, 23))
+
+    id: number;
+>id : Symbol(TodoProp.id, Decl(tsxSpreadChildren.tsx, 9, 20))
+
+    todo: string;
+>todo : Symbol(TodoProp.todo, Decl(tsxSpreadChildren.tsx, 10, 15))
+}
+interface TodoListProps {
+>TodoListProps : Symbol(TodoListProps, Decl(tsxSpreadChildren.tsx, 12, 1))
+
+    todos: TodoProp[];
+>todos : Symbol(TodoListProps.todos, Decl(tsxSpreadChildren.tsx, 13, 25))
+>TodoProp : Symbol(TodoProp, Decl(tsxSpreadChildren.tsx, 7, 23))
+}
+function Todo(prop: { key: number, todo: string }) {
+>Todo : Symbol(Todo, Decl(tsxSpreadChildren.tsx, 15, 1))
+>prop : Symbol(prop, Decl(tsxSpreadChildren.tsx, 16, 14))
+>key : Symbol(key, Decl(tsxSpreadChildren.tsx, 16, 21))
+>todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 16, 34))
+
+    return <div>{prop.key.toString() + prop.todo}</div>;
+>div : Symbol(JSX.IntrinsicElements, Decl(tsxSpreadChildren.tsx, 2, 22))
+>prop.key.toString : Symbol(Number.toString, Decl(lib.d.ts, --, --))
+>prop.key : Symbol(key, Decl(tsxSpreadChildren.tsx, 16, 21))
+>prop : Symbol(prop, Decl(tsxSpreadChildren.tsx, 16, 14))
+>key : Symbol(key, Decl(tsxSpreadChildren.tsx, 16, 21))
+>toString : Symbol(Number.toString, Decl(lib.d.ts, --, --))
+>prop.todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 16, 34))
+>prop : Symbol(prop, Decl(tsxSpreadChildren.tsx, 16, 14))
+>todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 16, 34))
+>div : Symbol(JSX.IntrinsicElements, Decl(tsxSpreadChildren.tsx, 2, 22))
+}
+function TodoList({ todos }: TodoListProps) {
+>TodoList : Symbol(TodoList, Decl(tsxSpreadChildren.tsx, 18, 1))
+>todos : Symbol(todos, Decl(tsxSpreadChildren.tsx, 19, 19))
+>TodoListProps : Symbol(TodoListProps, Decl(tsxSpreadChildren.tsx, 12, 1))
+
+    return <div>
+>div : Symbol(JSX.IntrinsicElements, Decl(tsxSpreadChildren.tsx, 2, 22))
+
+        {...todos.map(todo => <Todo key={todo.id} todo={todo.todo}/>)}
+>todos.map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>todos : Symbol(todos, Decl(tsxSpreadChildren.tsx, 19, 19))
+>map : Symbol(Array.map, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
+>todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 21, 22))
+>Todo : Symbol(Todo, Decl(tsxSpreadChildren.tsx, 15, 1))
+>key : Symbol(key, Decl(tsxSpreadChildren.tsx, 16, 21))
+>todo.id : Symbol(TodoProp.id, Decl(tsxSpreadChildren.tsx, 9, 20))
+>todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 21, 22))
+>id : Symbol(TodoProp.id, Decl(tsxSpreadChildren.tsx, 9, 20))
+>todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 16, 34))
+>todo.todo : Symbol(TodoProp.todo, Decl(tsxSpreadChildren.tsx, 10, 15))
+>todo : Symbol(todo, Decl(tsxSpreadChildren.tsx, 21, 22))
+>todo : Symbol(TodoProp.todo, Decl(tsxSpreadChildren.tsx, 10, 15))
+
+    </div>;
+>div : Symbol(JSX.IntrinsicElements, Decl(tsxSpreadChildren.tsx, 2, 22))
+}
+let x: TodoListProps;
+>x : Symbol(x, Decl(tsxSpreadChildren.tsx, 24, 3))
+>TodoListProps : Symbol(TodoListProps, Decl(tsxSpreadChildren.tsx, 12, 1))
+
+    <TodoList {...x}/>
+>TodoList : Symbol(TodoList, Decl(tsxSpreadChildren.tsx, 18, 1))
+>x : Symbol(x, Decl(tsxSpreadChildren.tsx, 24, 3))
+

tests/baselines/reference/tsxSpreadChildren.types

@@ -0,0 +1,94 @@
+=== tests/cases/conformance/jsx/tsxSpreadChildren.tsx ===
+
+declare module JSX {
+>JSX : any
+
+	interface Element { }
+>Element : Element
+
+	interface IntrinsicElements {
+>IntrinsicElements : IntrinsicElements
+
+		[s: string]: any;
+>s : string
+	}
+}
+declare var React: any;
+>React : any
+
+interface TodoProp {
+>TodoProp : TodoProp
+
+    id: number;
+>id : number
+
+    todo: string;
+>todo : string
+}
+interface TodoListProps {
+>TodoListProps : TodoListProps
+
+    todos: TodoProp[];
+>todos : TodoProp[]
+>TodoProp : TodoProp
+}
+function Todo(prop: { key: number, todo: string }) {
+>Todo : (prop: { key: number; todo: string; }) => JSX.Element
+>prop : { key: number; todo: string; }
+>key : number
+>todo : string
+
+    return <div>{prop.key.toString() + prop.todo}</div>;
+><div>{prop.key.toString() + prop.todo}</div> : JSX.Element
+>div : any
+>prop.key.toString() + prop.todo : string
+>prop.key.toString() : string
+>prop.key.toString : (radix?: number) => string
+>prop.key : number
+>prop : { key: number; todo: string; }
+>key : number
+>toString : (radix?: number) => string
+>prop.todo : string
+>prop : { key: number; todo: string; }
+>todo : string
+>div : any
+}
+function TodoList({ todos }: TodoListProps) {
+>TodoList : ({todos}: TodoListProps) => JSX.Element
+>todos : TodoProp[]
+>TodoListProps : TodoListProps
+
+    return <div>
+><div>        {...todos.map(todo => <Todo key={todo.id} todo={todo.todo}/>)}    </div> : JSX.Element
+>div : any
+
+        {...todos.map(todo => <Todo key={todo.id} todo={todo.todo}/>)}
+>todos.map(todo => <Todo key={todo.id} todo={todo.todo}/>) : JSX.Element[]
+>todos.map : { <U>(this: [TodoProp, TodoProp, TodoProp, TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [TodoProp, TodoProp, TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [TodoProp, TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U, U]; <U>(this: [TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): U[]; }
+>todos : TodoProp[]
+>map : { <U>(this: [TodoProp, TodoProp, TodoProp, TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U, U, U, U]; <U>(this: [TodoProp, TodoProp, TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U, U, U]; <U>(this: [TodoProp, TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U, U]; <U>(this: [TodoProp, TodoProp], callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): [U, U]; <U>(callbackfn: (value: TodoProp, index: number, array: TodoProp[]) => U, thisArg?: any): U[]; }
+>todo => <Todo key={todo.id} todo={todo.todo}/> : (todo: TodoProp) => JSX.Element
+>todo : TodoProp
+><Todo key={todo.id} todo={todo.todo}/> : JSX.Element
+>Todo : (prop: { key: number; todo: string; }) => JSX.Element
+>key : any
+>todo.id : number
+>todo : TodoProp
+>id : number
+>todo : any
+>todo.todo : string
+>todo : TodoProp
+>todo : string
+
+    </div>;
+>div : any
+}
+let x: TodoListProps;
+>x : TodoListProps
+>TodoListProps : TodoListProps
+
+    <TodoList {...x}/>
+><TodoList {...x}/> : JSX.Element
+>TodoList : ({todos}: TodoListProps) => JSX.Element
+>x : TodoListProps
+

tests/baselines/reference/tsxSpreadChildrenInvalidType.errors.txt

@@ -0,0 +1,38 @@
+tests/cases/conformance/jsx/tsxSpreadChildrenInvalidType.tsx(21,9): error TS2609: JSX spread child must be an array type.
+
+
+==== tests/cases/conformance/jsx/tsxSpreadChildrenInvalidType.tsx (1 errors) ====
+    declare module JSX {
+    	interface Element { }
+    	interface IntrinsicElements {
+    		[s: string]: any;
+    	}
+    }
+    declare var React: any;
+
+    interface TodoProp {
+        id: number;
+        todo: string;
+    }
+    interface TodoListProps {
+        todos: TodoProp[];
+    }
+    function Todo(prop: { key: number, todo: string }) {
+        return <div>{prop.key.toString() + prop.todo}</div>;
+    }
+    function TodoList({ todos }: TodoListProps) {
+        return <div>
+            {...<Todo key={todos[0].id} todo={todos[0].todo} />}
+            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2609: JSX spread child must be an array type.
+        </div>;
+    }
+    function TodoListNoError({ todos }: TodoListProps) {
+        // any is not checked
+        return <div>
+            {...(<Todo key={todos[0].id} todo={todos[0].todo} /> as any)}
+        </div>;
+    }
+    let x: TodoListProps;
+        <TodoList {...x}/>
+