Add Engine ESM build

[marklundin]

This PR adds an additional ES6 bundle playcanvas.esm.js as a build output. It uses the same ES6 build configuration as the unbundled playcanvas.mjs but instead simply outputs to a single output.

We plan on upgrading the launcher and exported projects to use this ES6 build to support ESM Scripts.

I confirm I have read the contributing guidelines and signed the Contributor License Agreement.

[kungfooman]

Very nice, people needed this for quite some time - unbundled ESM builds were causing:

• no problem for local development, but long request times for every individual file over internet
• services like UNPKG have request limits and simply drop further ones

[marklundin]

Very nice, people needed this for quite some time - unbundled ESM builds were causing:

• no problem for local development, but long request times for every individual file over internet
• services like UNPKG have request limits and simply drop further ones

Unfortunately even the ES Modules build includes these polyfils which are likely redundant

[kungfooman]

In the current file extension scheme .js means UMD, shouldn't we keep .mjs? Maybe something like playcanvas.bundled.mjs

[marklundin]

Yeah there's no easy answer here. playcanvas.mjs is the most obvious, and consistent with the UMD playcanvas.js build, but the .mjs suffix is currently pointing to a directory, and so I wonder if that build actually needs to be renamed

[mvaligursky]

Should we have other flavours of this bundle? At least debug, performance, and release (normal).

[marklundin]

Should we have other flavours of this bundle? At least debug, performance, and release (normal).

Yep there's the same outputs, dbg, prf and min

[slimbuck]

Had a little discussion among the team and we'd vote for:
playcanvas.js - the UMD build, as before
playcanvas.mjs - the ESM bundled version
playcanvas - the ESM unbundled version

And of course .dgb, .min, .profile version of each.

[kungfooman]

We also need to change in that case:

engine/package.json

Line 21 in 6314936

"module": "build/playcanvas.mjs/index.js",

[marklundin]

Had a little discussion among the team and we'd vote for: playcanvas.js - the UMD build, as before playcanvas.mjs - the ESM bundled version playcanvas - the ESM unbundled version

And of course .dgb, .min, .profile version of each.

Love this. Done!

Assuming the unbundled 'playcanvas' dir doesn't need to have 'playcanvas.prf', 'playcanvas.min', 'playcanvas.dbg' variants

[marklundin]

We also need to change in that case:

engine/package.json

Line 21 in 6314936

"module": "build/playcanvas.mjs/index.js",

Yep agreed. Have updated

[slimbuck]

Assuming the unbundled 'playcanvas' dir doesn't need to have 'playcanvas.prf', 'playcanvas.min', 'playcanvas.dbg' variants

I think we will need variants... @mvaligursky ?

[marklundin]

What would be the naming convention on these folders? Having the dot suffix doesn't feel right. kebab case 'playcanvas-dbg/index.js' might work if we do

[mvaligursky]

If we expect people to use the unbundled versions, we need to provide the variants, as they cannot easily replicate our processes to strip out debug info, and they need debug version at the very least.

[slimbuck]

For consistency naming the folders playcanvas, playcanvas.dbg, playcanvas.min, playcanvas.prf seems fine to me.

[slimbuck]

Though in reality the .min unbundled build has no use whatsoever (the rest do).

[marklundin]

Have added unbundled es6 variants excluding 'min' @slimbuck @mvaligursky

[slimbuck]

<3