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.

1 files changed, 28 insertions, 0 deletions

diff --git a/std/types/README.md b/std/types/README.md
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+# std/types
+
+Contains types for popular external packages that are compatible with Deno.
+
+Because Deno only resolves fully qualified file names, type definitions that
+import other type definitions might not work with Deno. Also, when some type
+definition supply some global interfaces, they can conflict with Deno. The types
+located here have been validated to work with Deno.
+
+The types that are currently available:
+
+- `react.d.ts` - For React 16. Sources known to work well for Deno:
+  - Pika CDN: `https://cdn.pika.dev/_/react/v16`
+  - JSPM: `https://dev.jspm.io/react@16`
+- `react-dom.d.ts` - For ReactDOM 16. Sources known to work well for Deno:
+  - Pika CDN: `https://cdn.pika.dev/_/react-dom/v16`
+  - JSPM: `https://dev.jspm.io/react-dom@16`
+
+There are several ways these type definitions can be referenced. Likely the
+"best" way is that the CDN provider provides a header of `X-TypeScript-Types`
+which points to the type definitions. We are working to have this available, but
+currently you would need to use the compiler hint of `@deno-types`. For example
+to import React:
+
+```ts
+// @deno-types="https://deno.land/std/types/react.d.ts"
+import React from "https://cdn.pika.dev/_/react/v16";
+```