[suggest] improve compatibility with more estree parsers?

[3cp]

I am trying to use eslint-scope with meriyah which uses different data structure for ranges.

It doesn't have .range: [start, end], but has direct .start and .end.

eslint-scope/lib/scope.js

Lines 711 to 718 in dbddf14

	const bodyStart = this.block.body.range[0];
	// It's invalid resolution in the following case:
	return !(
	variable.scope === this &&
	ref.identifier.range[0] < bodyStart && // the reference is in the parameter part.
	variable.defs.every(d => d.name.range[0] >= bodyStart) // the variable is in the body.
	);

If I update the above code from .range[0] to .start, everything works fine with meriyah.

Do you consider to improve compatibility with other estree parsers? To check both .range[0] and .start? Thanks!

FYI, estree spec seems didn't define the shape of ranges, it only defined position. https://github.com/estree/estree/blob/14df8a024956ea289bd55b9c2226a1d5b8a473ee/es5.md#node-objects

[aladdin-add]

I'm not sure we can go that way, as .start/.end is non-standard and non-recommended.

Related issue(s): RFC25, eslint/eslint#12096, eslint/eslint#12955

[3cp]

Oh, thx! I did not know it got that much complications.

[3cp]

I noticed it is acknowledged that both .range and .start .end are non-standard. Same as what I read from estree spec. eslint/eslint#8956

[3cp]

I think there is an opportunity to improve.

It's not about .range[0] or .start. I felt this check is doable even without any ranges information, because we knew where the node was (in params or body).

The reason of using ranges to check, is that the reference and definition objects didn't retain that information (in params or body). I am not sure how to retain that information in nested function scopes.

I could not get my head around the code base to come up a solution. But I think it's possible to totally remove the usage of .range[0].

[bradzacher]

If you're looking for a completely estree-compliant version, isn't that what escope is?

[3cp]

I came here to find an up-to-date version of escope 😄

[nzakas]

As mentioned previously, the start and stop properties are not part of ESTree. They only appear in Espree because we are built on Acorn, which adds these nonstandard properties. Removing them incurs a performance penalty so we leave them in place. However, we don’t rely on those properties being present and always use range internally.

Because we don’t want to encourage relying on nonstandard properties, we won’t be updating this package to use start and end.

Thanks!

[3cp]

But I think it's possible to totally remove the usage of .range[0].

@nzakas you probably missed my comment on reopening of the issue.