What is the difference between matcher and filter?

[callumlocke]

This might be a documentation issue, or maybe I'm being stupid.

The readme says that .matcher(pattern) gets you a function that you can use to match paths. I'm assuming this means it returns true/false, in which case it sounds like it could be used as an array filter function.

But then there seems to be another method for this exact purpose, .filter(): "Returns a function that can be passed to Array#filter()." I don't get it. Can't the returned function from .matcher be used in this way?

What's the difference?

[es128]

I can't speak to why both needed to be provided in the API, but here's the difference as far as I can tell:

filter works with one or more glob patterns.

matcher works with one criterion (not an array) and allows regexes and functions as well as glob patterns as the input.

[jonschlinkert]

Yeah, the differences that @es128 pointed out are correct, but I've thought about removing filter. Maybe we can allow matcher to handle multiple patterns, and get rid of filter next time we make major changes

[callumlocke]

Maybe we can allow matcher to handle multiple patterns, and get rid of filter next time we make major changes

That sounds good, less confusing.

In the mean time, do I understand correctly that mm.filter(x)(filename) should always work identically to mm(filenames, x), no matter what type x is?

[jonschlinkert]

What's the use case? might be easier to give good feedback based on what you're trying to accomplish.

[callumlocke]

The mm() function works like this:

Negation patterns:
Behavior;

• when the pattern is a string, minimatch behavior is used, so patterns are inclusive by default.
• when an array of patterns is passed, multimatch behavior is used, so patterns are exclusive by default

Does the function I get back from mm.filter(x) have that same behaviour (i.e. it can either be inclusive or exclusive, depending on whether x is an array or a string)?

[jonschlinkert]

can [filter] either be inclusive or exclusive, depending on whether x is an array or a string)?

it should, yes. see these unit tests for examples

[jonschlinkert]

closing since it's not technically an issue. feel free to continue the conversation or open a new issue if a new topic pops up