std: Provide types for React and ReactDOM (#4376)

Introduces `std/types` which is designed to provide types for common
libraries that are compatible with Deno.

4 files changed, 61 insertions, 0 deletions

diff --git a/std/types/tests/react-dom_mock.js b/std/types/tests/react-dom_mock.js
new file mode 100644
index 000000000..68b4137ba
--- /dev/null
+++ b/std/types/tests/react-dom_mock.js
@@ -0,0 +1,9 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+const ReactDOM = {
+  render(element) {
+    return JSON.stringify(element);
+  }
+};
+
+export default ReactDOM;
diff --git a/std/types/tests/react-dom_test.tsx b/std/types/tests/react-dom_test.tsx
new file mode 100644
index 000000000..738227b65
--- /dev/null
+++ b/std/types/tests/react-dom_test.tsx
@@ -0,0 +1,20 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+// @deno-types="../react.d.ts"
+import React from "./react_mock.js";
+// @deno-types="../react-dom.d.ts"
+import ReactDOM from "./react-dom_mock.js";
+
+import { assertEquals } from "../../testing/asserts.ts";
+
+const { test } = Deno;
+
+test({
+  name: "ReactDOM is typed to render",
+  fn() {
+    assertEquals(
+      ReactDOM.render(<div />, null),
+      '"{\\"type\\":\\"div\\",\\"props\\":null,\\"children\\":[]}"'
+    );
+  }
+});
diff --git a/std/types/tests/react_mock.js b/std/types/tests/react_mock.js
new file mode 100644
index 000000000..93faa6c9b
--- /dev/null
+++ b/std/types/tests/react_mock.js
@@ -0,0 +1,9 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+const React = {
+  createElement(type, props, ...children) {
+    return JSON.stringify({ type, props, children });
+  }
+};
+
+export default React;
diff --git a/std/types/tests/react_test.tsx b/std/types/tests/react_test.tsx
new file mode 100644
index 000000000..f9ffc471a
--- /dev/null
+++ b/std/types/tests/react_test.tsx
@@ -0,0 +1,23 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+// @deno-types="../react.d.ts"
+import React from "./react_mock.js";
+import { assertEquals } from "../../testing/asserts.ts";
+
+const { test } = Deno;
+
+test({
+  name: "JSX can be rendered",
+  fn() {
+    class Component {
+      render() {
+        return <div></div>;
+      }
+    }
+
+    assertEquals(
+      new Component().render(),
+      `{"type":"div","props":null,"children":[]}`
+    );
+  }
+});