Adds no-dupe-args check to lint

[zinyando]

Adds a no-dupe-args check to lint on #94

[yangshun]

CI linting is failing due to a bug in the new rule - https://github.com/facebookexperimental/rome/pull/99/checks?check_run_id=479521121

The implementation assumes that all function parameters are identifiers (type: 'Identifier') which is not always the case. Perhaps we can ignore the non-identifiers, which is what ESLint seems to be doing.

Please add tests as well. You can refer to the ESLint tests for the possible kinds of functions - https://github.com/eslint/eslint/blob/master/tests/lib/rules/no-dupe-args.js

[sebmck]

This lint rule only works on regular name parameters, we can make it work more reliably, and support patterns with the getBindingIdentifiers method.

import {getBindingIdentifiers} from '@romejs/js-ast-utils';

The usage would be like this:

for (const param of node.params) {
  for (const {name} of getBindingIdentifiers(param)) {
    // logic here
  }
}

Then you can just maintain a single Set<string> with the checked arguments, then when found, produce a diagnostic.

Try to avoid the creation of duplicate AST arrays. For example, you used .filter(). Also avoid the usage of .forEach and instead use a regular for-of loop.

[sebmck]

An example of the pattern I'm referring to is #98.

[weblancaster]

@zinyando would we be able to re-implement this algorithm by trying to target linear O(N) instead quadratic time O(N²)? unless these are really small and we shouldn't care about the performance.

[sebmck]

There isn't a more efficient way to do this. param could have multiple binding identifiers, which is what this will extract.

[weblancaster]

I see. thanks.

[sebmck]

Thank you!