On a recent project, I found myself filtering an array and then re-filtering that array to get the items that didn't match the filter.
This function behaves the same as Array.filter and _.filter, but it returns two results. The first item in the array contains an array of all of the items that the filter returns true for, and the second item contains and array of all the items where the filter returns false.
const splitFilter = require('@edorsey/split-filter')
const arrayToSplit = [1, 2, "a", 3, "b", "c", 4, []]
const [stringResults, leftovers] = splitFilter(arrayToSplit, (item) => typeof item === "string")
stringResults //["a", "b", "c"]
leftovers //[1, 2, 3, 4, []]