'with' optional callback

[alepeino]

Adds an optional callback as 2nd argument to helper with, to mutate the value before returning it.

If it's preferred not to overload this function, thru may be a good alternative name (same functionality as Lodash function with the same name).

[morloderex]

This sounds a lot like you need to use a tap call instead.

[alepeino]

@morloderex Well, it's not quite the same (that's why I referenced Lodash thru). I basically use tap for two purposes:

• Side effects:

tap($model, function ($m) { $m->save(); })

• Objects with an internal state:

tap($model, function ($m) { $m->key = 'value'; })

But tap won't help for cases such as the simple ones I show in the tests. Like, if I don't want to mutate the object state, just get a new state which is a function of the first.

Anyway, this is closed now ¯\_(ツ)_/¯