index

Get zero-based index for an element in array.

Similar: index, indexRange, size, isEmpty.

function index(x, i)
// x: an array
// i: ±index

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

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

xarray.index(x, -1);
// → 3

xarray.index(x, -10);
// → 0

References

• Array.slice() : MDN Web Docs