Feature request: require node "^12 || >=14" and support "type": "module"

[TomerAberbach]

From what I can tell, it's not currently possible to run generators written as ESM modules/"type": "module". This is a feature request for that to be possible!

I took a look at the code and I think these lines in lib/store.js could be modified like so to support both CJS and ESM:

Object.defineProperty(this._generators, namespace, {
- get() {
-   const Generator = require(path);
+ async get() {
+   const Generator = await import(require.resolve(path));
    return Generator;
  },
  enumerable: true,
  configurable: true
});

Of course, that's not the end of the story. Then every usage of this.generators[something], directly or transitively, must be updated to support asynchronous importing of generators. I would expect some public API methods would be affected. Also, dynamic import's module resolution strategy is different than require's.

So basically, this would definitely be a breaking change, but I think it's an essential change now that ESM is becoming the preferred module format.

Let me know if you'd like any help with this. I'd be keen to help! 😃

[mshima]

Implemented today.

• Why not keep ">=12.10.0"? Not planning to change it.

It won't be a breaking change.
Composing with a esm generator will have a different behavior, it will return a promise instead a generator.

[TomerAberbach]

Implemented today.

Do you mean that ESM generators are already supported? I personally couldn't get it to work, but maybe I was doing something wrong.

• Why not keep ">=12.10.0"? Not planning to change it.

I think that the earliest Node version where ESM, including dynamic import, is supported unflagged is v12.17.0. So you'd have to require ">= 12.17.0" at least if dynamic import is in your code (I think it's a syntax error prior to v12.17.0).

It won't be a breaking change.
Composing with a esm generator will have a different behavior, it will return a promise instead a generator.

Sure, I suppose you could try to have different behavior between CJS and ESM generators.

[mshima]

ESM support is added to 3.4.0

[TomerAberbach]

Just tried it out! Confirmed it works 🥳

Great work! 😄