Support import maps and bare import specifiers

[bahrus]

Suggestion

🔍 Search Terms

1. import maps
2. bare import specifiers

✅ Viability 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, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

As import maps are part of Chrome (as of version 89), and Firefox has given a nod of approval, it would be great if Typescript embraced this cross-package import syntax.

Import maps assume an index.html (for example) file with a script tag, e.g.:

<script type="importmap">
{
  "imports": {
    "moment": "/node_modules/moment/src/moment.js",
    "lodash": "/node_modules/lodash-es/lodash.js"
  }
}
</script>

I would suggest being able to

1. Point to a file containing such an importmap in tsconfig and/or
2. Just supporting bare import specifiers, based on package.json/package-lock.json, the way unpkg.com is able to do..

📃 Motivating Example

Now you can reference cross-package JS files seamlessly, without bundling tools, based on browser standards.

Workaround:

The path resolution Typescript provides is inadequate, and quite unhelpful.

The only fairly reliable workaround I've found is cloning the repo to a sibling folder of my project.

[matthew-dean]

I would love to see this implemented in Node.js, and then just automatically picked up by TypeScript as an alternative to paths.

Edit: Oh hang on, this blog post claims it is implemented in Node? https://blog.spencersnyder.io/solving-the-long-relative-paths-problem-natively-in-node-js-6aeebc3a81bd. Can TypeScript just pick this up the import key to resolve?

[CMCDragonkai]

It seems that at the moment one has to still specify paths mapping in tsconfig.json to get tsc to understand the #internal paths that now exists in package.json for NodeJS packages.