Deno: Support dynamic import

[hayd]

I know this is already on the radar, but wanted to create a distinct issue.

(This is required for a test runner.)

[aymonYU]

I also need this feature！！！

[kitsonk]

Just to be clear, this was implemented but during the re-write to use ESM natively, it had to be dropped to be re-implemented later. It is currently sitting in @ry's backlog.

[ry]

This should happen in //core/ ... https://github.com/denoland/deno/pull/1919 needs to land first.

[ry]

I want to complete async module loading before attempting this (which is essentially the same as this progress bar issue: https://github.com/denoland/deno/issues/1320)

[somombo]

update: async module loading has landed https://github.com/denoland/deno/pull/2084

[Fenzland]

That's great happy that you are working for this key feature. but it's not work until 0.9.0. Here is what's happened on my computer, maybe help.

Environment

deno version

deno: 0.9.0
v8: 7.7.37
typescript: 3.5.1

on Ubuntu 18.04

Files

test-dynamic-import.js

import('./imported.js').then( module=> {
    console.log( module.default );
}, );

imported.js

export default 'successful';

Result:

deno run test-dynamic-import.js

thread 'tokio-runtime-worker-0' panicked at 'dyn_import callback not set', ../../core/isolate.rs:238:7
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
fatal runtime error: failed to initiate panic, error 5
bash: “deno run test-dynamic-import.js” terminated by signal SIGABRT (Abort)

[kitsonk]

This has not been delivered yet. That is why the issue is still open. It is still being worked on.

[ry]

Almost there... https://github.com/denoland/deno/pull/2678 was landed which adds better error handling in libdeno's dynmaic import binding. We now just need to rebase #2516 ...

[bartlomieju]

Done with #2516 :)

CC @ry

[nvlled]

Is there an option to disable caching the imported file? Maybe something like import('file.ts', {cache: false})

[kitsonk]

That would be a seperate request.

Also, import() might look like a function, but it isn't, it is actually low level syntax and cannot be augmented.

[nvlled]

Looks like there's already one here https://github.com/denoland/deno/issues/5548
And there's a workaround here https://github.com/denoland/deno/issues/5548#issuecomment-643647953