import defer

[nicolo-ribaudo]

Specification

https://github.com/tc39/proposal-defer-import-eval/

Description

import defer allows importing JavaScript modules while deferring their evaluation to first usage, synchronously.

Documentation

The proposal (https://github.com/tc39/proposal-defer-import-eval/) has some docs, but it's not on MDN yet

Browser support

• Behind a flag in V8
• https://bugzilla.mozilla.org/show_bug.cgi?id=1952263
• https://bugs.webkit.org/show_bug.cgi?id=286272
• https://chromestatus.com/feature/5071131271888896
• https://chromestatus.com/feature/6090846000775168

[nicolo-ribaudo]

test262 calls this import-defer, if we want to have the same label.

[ddbeck]

Hi @nicolo-ribaudo, thank you for filing this issue. I'm mostly taking notes for myself here to create the feature entry, but if you'd like to check it for accuracy (on the parts that are familiar to you) that would be welcome.

• The ID is likely to be import-defer, as suggested.

• The name for this feature is likely to follow the syntax: "import defer"

• The description for this feature, in our style, is likely to be something like:

  The import defer JavaScript declaration delays evaluation of an imported module until its first use.

• For browser support, I don't think this is shipping anywhere yet. I flagged this issue as an early feature. I did find these (and added them to the issue description):

  • https://bugzilla.mozilla.org/show_bug.cgi?id=1952263
  • https://bugs.webkit.org/show_bug.cgi?id=286272
  • https://chromestatus.com/feature/5071131271888896 and https://chromestatus.com/feature/6090846000775168 (I'm not sure of the distinction between the two.)

• When this does get to a beta in a browser, then I'd expect this mdn/browser-compat-data keys to appear: javascript.statements.import.defer.