30-seconds-of-code/snippets/array-difference.md

Array difference (complement)

Create a Set from b, then use Array.filter() on a to only keep values not contained in b.

const difference = (a, b) => { const s = new Set(b); return a.filter(x => !s.has(x)); }
// difference([1,2,3], [1,2]) -> [3]