instanceOf()

[Qix-]

Need instanceOf()!

[sindresorhus]

I honestly never use instanceof. What do you use it for?

We might pass on this unless there's strong opinions otherwise as we're trying to keep this module small and focused. Can always use heavier assertion libs if you need something like this. Keeping it open for discussion though.

[arthurvr]

Yeah, me neighter. I practically never use it.

[tunnckoCore]

Yeah, me neighter. I practically never use it.

👍 Only place i use it is assert.throws(fn, TypeError) + assert.throws(fn, msg) combo.

[Qix-]

async.each([1, 2, 3], function (cb) {
  claim.instanceOf(cb, Function); // make sure async is correctly passing me a function callback
});

Obviously I'm not writing tests for async, but I over-test my frameworks to make sure they're giving me exactly what I'm expecting.

[tunnckoCore]

why not?

async.each([1, 2, 3], function (cb) {
  claim.is(cb instanceof Function, true); // make sure async is correctly passing me a function callback
});

[Qix-]

For the same reason

claim.is(1, 1);

instead of

claim.true(1 === 1)

[sindresorhus]

@Qix-

claim.instanceOf(cb, Function); → claim.is(typeof cb, 'function');

You shouldn't use instanceof with Function as it won't work if it comes from another realm like windows/frames in the browser. And with typeof, you can just use .is().

[Qix-]

@sindresorhus I understand, though in Node in particular that isn't a problem. If I need to check instanceof for anything, not even Functions in particular, then I have to use instanceof. claim could even do

claim.instanceOf(obj, SomeFunction); // obj.constructor.name === SomeFunction.name

Using .is() defeats the purpose of a library re-creating these methods for better error output, right?

[sindresorhus]

Seeing as this is IMHO and obscure case, I'd prefer we go with power-assert on this one.

claim.ok(obj instanceOf SomeFunction);

avajs/ava#46

[Qix-]

Agreed with that.