Feature request: add support for the .cjs file extension

[cedx]

Since Node.js 12.x (I don't know the exact version: maybe since 12.11.0), we can use the .cjs file extension to denote a JS file using the CommonJS module format.

The issue: if we use "type": "module" in package.json file, every file which extension ends with .js is interpreted as an ES module. With this setting, Gulp fails when loading the gulpfile.js file. The only way to force Node.js to interpret the Gulp file as a CommonJS module is to rename it as gulpfile.cjs.

If we do this, Gulp doesn't find anymore the gulpfile.cjs by itself. We need to use the --gulpfile or -f command file, which is cumbersome.

[cedx]

We can use a .gulp.json file at the project root to avoid the need to pass the -f option on command line:

{
  "flags": {
    "gulpfile": "gulpfile.cjs"
  }
}

I close this ticket because this solution suits me.

[phated]

@cedx since node supports .cjs natively, I think we can set .cjs to null in the config but I still need to check.

[cedx]

Probably: when I tried, it worked. At least, locally (see #60).
(I closed this issue and the related PR because I had too many issues and PR open, and I wanted to do a cleanup of my GitHub account)
Thanks for your efforts on Gulp!

[phated]

It seems that this is only supposed to work when you are executing something with the node command directly or importing a .cjs file from a .mjs file.

I'm not sure why your solution is actually working 😬

[phated]

It also seems like .cjs doesn't exist in require.extensions, which this module is primarily concerned with.

I don't think we can support .cjs right now and the workaround will need to suffice. Sorry.