Feature request: `combinations`

[itzTheMeow]

Would be similar to this implementation: https://github.com/SeregPie/lodash.combinations

lodash.combinations

_.combinations(collection, k)

Calculates all possible combinations without repetition of a certain size.

argument	description
collection	A collection of distinct values to calculate the groups from.
k	A number as the size of each group.

Returns the calculated groups as an array of arrays.

Calculate all possible combinations of all possible sizes.

let combinations = _.flatMap([2, 4, 6], (v, i, a) => _.combinations(a, i + 1));
// => [[2], [4], [6], [2, 4], [2, 6], [4, 6], [2, 4, 6]]