Fix children prop for react-jsx and react-jsxdev (#40630)

* Fix children prop for `react-jsx` and `react-jsxdev`

* Add tests

Author: latin-1

src/compiler/transformers/jsx.ts

@@ -208,33 +208,36 @@ namespace ts {
             let objectProperties: Expression;
             const keyAttr = find(node.attributes.properties, p => !!p.name && isIdentifier(p.name) && p.name.escapedText === "key") as JsxAttribute | undefined;
             const attrs = keyAttr ? filter(node.attributes.properties, p => p !== keyAttr) : node.attributes.properties;
-            if (attrs.length === 0) {
-                objectProperties = factory.createObjectLiteralExpression([]);
-                // When there are no attributes, React wants {}
-            }
-            else {
+
+            let segments: Expression[] = [];
+            if (attrs.length) {
                 // Map spans of JsxAttribute nodes into object literals and spans
                 // of JsxSpreadAttribute nodes into expressions.
-                const segments = flatten<Expression | ObjectLiteralExpression>(
+                segments = flatten(
                     spanMap(attrs, isJsxSpreadAttribute, (attrs, isSpread) => isSpread
                         ? map(attrs, transformJsxSpreadAttributeToExpression)
                         : factory.createObjectLiteralExpression(map(attrs, transformJsxAttributeToObjectLiteralElement))
                     )
                 );
 
-                if (children && children.length) {
-                    const result = convertJsxChildrenToChildrenPropObject(children);
-                    if (result) {
-                        segments.push(result);
-                    }
-                }
-
                 if (isJsxSpreadAttribute(attrs[0])) {
                     // We must always emit at least one object literal before a spread
                     // argument.factory.createObjectLiteral
                     segments.unshift(factory.createObjectLiteralExpression());
                 }
+            }
+            if (children && children.length) {
+                const result = convertJsxChildrenToChildrenPropObject(children);
+                if (result) {
+                    segments.push(result);
+                }
+            }
 
+            if (segments.length === 0) {
+                objectProperties = factory.createObjectLiteralExpression([]);
+                // When there are no attributes, React wants {}
+            }
+            else {
                 // Either emit one big object literal (no spread attribs), or
                 // a call to the __assign helper.
                 objectProperties = singleOrUndefined(segments) || emitHelpers().createAssignHelper(segments);

tests/baselines/reference/jsxJsxsCjsTransformChildren(jsx=react-jsx).js

@@ -0,0 +1,13 @@
+//// [jsxJsxsCjsTransformChildren.tsx]
+/// <reference path="/.lib/react16.d.ts" />
+const a = <div>text</div>;
+
+export {};
+
+
+//// [jsxJsxsCjsTransformChildren.js]
+"use strict";
+exports.__esModule = true;
+var jsx_runtime_1 = require("react/jsx-runtime");
+/// <reference path="react16.d.ts" />
+var a = jsx_runtime_1.jsx("div", { children: "text" }, void 0);

tests/baselines/reference/jsxJsxsCjsTransformChildren(jsx=react-jsx).symbols

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/jsx/jsxs/jsxJsxsCjsTransformChildren.tsx ===
+/// <reference path="react16.d.ts" />
+const a = <div>text</div>;
+>a : Symbol(a, Decl(jsxJsxsCjsTransformChildren.tsx, 1, 5))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react16.d.ts, 2420, 114))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react16.d.ts, 2420, 114))
+
+export {};
+

tests/baselines/reference/jsxJsxsCjsTransformChildren(jsx=react-jsx).types

@@ -0,0 +1,10 @@
+=== tests/cases/conformance/jsx/jsxs/jsxJsxsCjsTransformChildren.tsx ===
+/// <reference path="react16.d.ts" />
+const a = <div>text</div>;
+>a : JSX.Element
+><div>text</div> : JSX.Element
+>div : any
+>div : any
+
+export {};
+

tests/baselines/reference/jsxJsxsCjsTransformChildren(jsx=react-jsxdev).js

@@ -0,0 +1,14 @@
+//// [jsxJsxsCjsTransformChildren.tsx]
+/// <reference path="/.lib/react16.d.ts" />
+const a = <div>text</div>;
+
+export {};
+
+
+//// [jsxJsxsCjsTransformChildren.js]
+"use strict";
+exports.__esModule = true;
+var jsx_dev_runtime_1 = require("react/jsx-dev-runtime");
+var _jsxFileName = "tests/cases/conformance/jsx/jsxs/jsxJsxsCjsTransformChildren.tsx";
+/// <reference path="react16.d.ts" />
+var a = jsx_dev_runtime_1.jsxDEV("div", { children: "text" }, void 0, false, { fileName: _jsxFileName, lineNumber: 2, columnNumber: 10 }, this);

tests/baselines/reference/jsxJsxsCjsTransformChildren(jsx=react-jsxdev).symbols

@@ -0,0 +1,9 @@
+=== tests/cases/conformance/jsx/jsxs/jsxJsxsCjsTransformChildren.tsx ===
+/// <reference path="react16.d.ts" />
+const a = <div>text</div>;
+>a : Symbol(a, Decl(jsxJsxsCjsTransformChildren.tsx, 1, 5))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react16.d.ts, 2420, 114))
+>div : Symbol(JSX.IntrinsicElements.div, Decl(react16.d.ts, 2420, 114))
+
+export {};
+

tests/baselines/reference/jsxJsxsCjsTransformChildren(jsx=react-jsxdev).types

@@ -0,0 +1,10 @@
+=== tests/cases/conformance/jsx/jsxs/jsxJsxsCjsTransformChildren.tsx ===
+/// <reference path="react16.d.ts" />
+const a = <div>text</div>;
+>a : JSX.Element
+><div>text</div> : JSX.Element
+>div : any
+>div : any
+
+export {};
+

tests/cases/conformance/jsx/jsxs/jsxJsxsCjsTransformChildren.tsx

@@ -0,0 +1,7 @@
+// @jsx: react-jsx,react-jsxdev
+// @strict: true
+// @module: commonjs
+/// <reference path="/.lib/react16.d.ts" />
+const a = <div>text</div>;
+
+export {};