index

Gets zero-based index.

Similar: index, indexRange, length.

array.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