Support ESM

[stropho]

Follow up for #148
Since 2 years ago, there have been many new things in Node such as support for ECMAScript modules
It would be great to enable ESM support, at least to some extent.

Currently plopfile exports a function. The easiest workaround 1️⃣ I can think of is for the plopfile to export a function or a promise resolving a function. Then the plopfile could look like

module.exports = import('./my-esm-plopfile.mjs')

2️⃣ Another more robust solution could be

Plop.launch({
	// configPath: argv.plopfile,
	config: thePlopfileFunctionItself
}, run);

But after having a brief look on node-plop, it seems that this way would be more complicated, most likely a breaking change, because configPath is not used only for loading the plopfile 🤔

3️⃣ I'm sure there are other options as well 😄

What do you think, are the ES modules something worth supporting in plop ?

[crutchcorn]

This is 100% something we need to look into. To be honest, I am strongly considering migrating plop and node-plop itself into full ESM after some stabilization efforts (to make sure we don't break anything in the process)

[crutchcorn]

PlopJS 3 is releasing this Saturday, with ESM support!

It's stable and has a changelog today ( #293 ) but won't be launched until Saturday so that, in the event something goes wrong, I can support immediately.

[crutchcorn]

ESM modules in Plop are now supported as-of Plop 3!

https://github.com/plopjs/plop/releases/tag/v3.0.0