Add support for URI style import

まず関連する issue #28985 と #19942 を確認し、次に提案されている uriPaths と browser または Deno のモジュール解決が、コンパイラに既存のパスマッピングにどのように適合するかを調査します。受け入れるマッピング動作、環境変数の扱い、出力を伴わない解決のセマンティクスを定義します。URI の例に対する対応するカバレッジを含む合意済みの設計ができれば完了です。

Search Terms

browser es module import url

Suggestion

Related issues: #28985, #19942

In browser and deno, import from a "package" is different from the node style.

// it's valid in browser but not in TypeScript
import lodash from "https://unpkg.com/lodash-es@4.17.15/lodash.js";

// it's valid in deno but not in TypeScript
import { serve } from "https://deno.land/std@v0.24.0/http/server.ts";

Currently there is no way to let TypeScript automatically map the URI to another place like @types/* or $DENO_DIR/deps/https/deno.land/*

The current path can map a simple pattern of import module specifier to another place, but in the URI style import, a more flexible way to map the URI is required.

Proposal

(maybe add a new moduleResolution: browser)
Add a new uriPaths that allows to map from a RegExp to a local path. It will NOT effect the emitted code. Just a way to find the type definition for those URIs.

I'm willing to implement this feature but I'm not sure if TypeScript will accept this.

Use Cases

For TypeScript to find definition file for imports like https://unpkg.com/lodash

Examples

{
  "compilerOptions": {
    "uriPaths": {
      "https://unpkg.com/(.+?)@.+?/.+": "./node_modules/@types/$1",
      "https://deno.land/(.+?)@v.+?/(.+?)/(.+)": "$DENO_DIR/deps/https/deno.land/$1/$2/$3",
      "std:(.+)": "./node_modules/builtin-module-types/$1"
    }
  }
}

This rule map https://unpkg.com/lodash-es@4.17.15/lodash.js to @types/lodash-es

Map https://deno.land/std@v0.24.0/http/server.ts to $DENO_DIR/deps/https/deno.land/std/http/server.ts.

$DENO_DIR is an environment variable.
By default, on Windows, it's ~\AppData\Local\deno\deps\https\deno.land\std\http\server.ts.
By default on Linux, it is ~/.deno/deps/https/deno.land/std/http/server.ts.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.