How to exhaust all permutations of an array of elements

permutation.js

function * permutation (input) {
    let n = input.length
    if (n === 0) {
        yield []
    } else {
        let needle = input.pop()
        for (let p of permutation(input)) {
            for (let i = 0; i < n; i++) {
                let q = p.slice()
                q.splice(i, 0, needle)
                yield q
            }
        }
    }
}

/*
for (let p of permutation([1,2,3,4])) {
    console.log(p)
}
*/