Guard with isIterationCall

[jridgewell]

Stolen from lodash, used to determine if one of our underscore methods were called by _.each, _.map, or friends.

[megawac]

is this helper necessary?

[jridgewell]

Not necessarily, but there's a bit of duplication between isArrayLike and isIterationCall that'll get worse once I propose only considering ints and not floats as proper index.

[megawac]

Mind adding a test for this change

[jashkenas]

Please explain what this is doing, beyond what the previous "guard" flag was already doing?

[jdalton]

Please explain what this is doing, beyond what the previous "guard" flag was already doing?

It's a more thorough check for when a guard param isn't applicable, like in cases where it's a context param.

[jashkenas]

Maybe an example would help clarify? I'm don't see any changed tests in this PR.

[jgonggrijp]

For future reference, isIterationCall is a throw at the helper function suggested as part of #1865. Which is a bit overused here as you only need to use a guard or isIterationCall, not both. Also it's a breaking change and I'm not in favor of it.