Import module directly from unpkg

[candlerb]

I believe it should be possible to import ES modules directly from unpkg - working examples.

However it doesn't appear to work with xterm.js.

Try 1:

<script type="module">
import { Terminal } from 'https://unpkg.com/xterm@latest?module';
alert("OK!");
</script>

This redirects to /xterm@4.8.1?module which returns 404 with message "Package xterm@4.8.1 does not contain an ES module"

Try 2:

<script type="module">
import { Terminal } from 'https://unpkg.com/xterm@latest/lib/xterm.js?module';
alert("OK!");
</script>

This URL serves some minified Javascript, but the import aborts with:

Uncaught SyntaxError: The requested module 'https://unpkg.com/xterm@latest/lib/xterm.js?module' does not provide an export named 'Terminal'

Have I missed something, or would something need changing in xterm.js to support this?

[Tyriar]

Duplicate of #2878