adapt functions to functional style (iterable last)

[xgbuils]

Currently, iterum library use functions inspired by lodash. However, after reading more about functional programming and knowing another libraries like imlazy, ramda or lodash/fp, I prefer iterables in the last parameter.

[xgbuils]

However I will mantain the methods having two ways to operate with iterables. I mean:

Iterum([1, 2, 3]).map(e => 2 * e) // method style
Iterum.map(e => 2 * e, [1, 2, 3]) // functional style

[xgbuils]

This change produce some inconvenients for binary iterable functions like concat and zip.

For the almost functions we have this rule:

Iterum(iterable).map(cb) === Iterum.map(cb, iterable)
Iterum(iterable).reduce(cb, initial) === Iterum.reduce(cb, initial, iterable)
Iterum(iterable).padEnd(length, value) === Iterum.padEnd(length, value, iterable)

But if this rule is extrapolated to zip function we have:

Iterum(firstIterable).zip(secondIterable) === Iterum.zip(secondIterable, firstIterable)

Then Iterum.zip([1, 2], [3, 4]) returns

[
    [3, 1],
    [4, 2]
]

But it's not the intuitive result. Then, I should think more how to handle this type of functions.

[xgbuils]

Fixed!