flip

63 bytes

Usage

Return a new function that swaps the only two arguments of the original function. This is most useful for reversing the order of a “comparator” (i.e. a function used for sorting).

import * as _ from 'radashi'

const subtract = (a: number, b: number) => a - b

subtract(1, 2) // => -1
_.flip(subtract)(1, 2) // => 1

Note that functions with more than two arguments are not supported.