How can I access target name in a Parcel plugin?

[melted-away]

I'm using Parcel for a web extension project. I've defined 2 targets in package.json file:

"targets": {
    "firefox": {
        "engines": {
            "browsers": [
                "last 1 Firefox version"
            ]
        }
    },
    "chrome": {
        "engines": {
            "browsers": [
                "last 1 Chrome version"
            ]
        }
    }
}

I want to write a transformer (or any plugin which does the trick) to combine a manifest.json and manifest.{targetName}.json before collecting manifest dependencies.

So far I have learned that asset.env gives some info about the current environment. But I'm looking for a way to get the target name. Is there any way for it?

I've also ask the question on Stackoverflow:
https://stackoverflow.com/questions/72722727/how-can-i-access-target-name-in-a-parcel-plugin

[melted-away]

I've come up with a solution:
https://stackoverflow.com/a/72834908/10132738

[mischnic]

The reason why the target isn't available in a transformer is that multiple dependencies with different targets could resolve to a single asset. Then there no single target for that asset.

If you're seeing that modifying the package.json doesn't rerun the resolver, then you should list the package.json's file path in the invalidateOnFileChange array that can be returned in the resolver.

[melted-away]

I did so but didn't get what I expected. So I tried calling the default resolver's resolve() inside my custom resolver and then modified the result of the function:

const defaultResolver = require('@parcel/resolver-default').default[Symbol.for('parcel-plugin-config')];
.
.
let res = await defaultResolver.resolve({ specifier, dependency, options });
.
.
res.code = JSON.stringify(manifest);
res.invalidateOnFileChange.push(targetSpecificManifestFilePath);
res.invalidateOnFileCreate.push({ fileName: 'package.json', aboveFilePath: targetSpecificManifestFilePath });

But yet changes in manifest.json and manifest.*.json, while running npm run watch, doesn't trigger rebuild. However, all other changes in other files does trigger the rebuild.

[mischnic]

const defaultResolver = require('@parcel/resolver-default').default[Symbol.for('parcel-plugin-config')];

The correct way here to is just copy the default resolver's code and modify it. The whole reason everything's abstracted away into @parcel/node-resolver-core is to make modifying the resolver easy: https://github.com/parcel-bundler/parcel/blob/v2/packages/resolvers/default/src/DefaultResolver.js

Not sure Why the watching doesn't work. Sharing a more complete resolver would be helpful.

[melted-away]

This time I copied the default resolver code into my custom resolver. But still no luck.

[melted-away]

I've added you to my repository. So that would be great if you could have a look. Thanks!