Add lazily evaluation like Wu.js with iterator about dollar

[tsheaff]

What kind of interface were you considering? I see a few options.

let squaresIterator = $.lazy_map([1, 2, 3, 4], { $0 * $0 })

Another option is

let squaresIterator = $.Lazy.map([1, 2, 3, 4], { $0 * $0 })

The squaresIterator here would be an instance of Dollar.Iterator, and would hold onto the array and the function and apply it on successive calls to .next() (with helpers .currentIndex, .hasNext etc.) We can then extend Dollar.Iterator to have more helper methods like .toArray() or .each(function)

Thoughts @ankurp ?

[ankurp]

$.lazy.map is better options and I agree with creating another class for iterative which hold bunch of other info about the collection like current index etc.

[tsheaff]

Cool. I'm gonna implement on my fork and then pull request

[ankurp]

Thanks 👍

[ALJCepeda]

It's done.

[tsheaff]

Nice. Yes I dropped the ball on this (busy with other projects), excited to see the result.

[ankurp]

Done. Chained expressions are evaluated lazily https://github.com/ankurp/Dollar.swift/blob/master/Dollar/Dollar/Dollar.swift#L269

[alsotang]

awesome!