index

Get zero-based index for element in array.

Similar: index, indexRange, size, isEmpty.

function index(x, i)
// x: an array
// i: index (-ve: from right)

const array = require('extra-array');

var x = [2, 4, 6, 8];
array.index(x, 1);
// → 1

array.index(x, -1);
// → 3

array.index(x, -10);
// → 0

References

• Array.prototype.slice: MDN web docs