Gets index range of part of array.
Similar: index, indexRange, size, isEmpty.
This is part of package extra-array.
array.indexRange(x, [i], [I]);
// x: an array
// i: start index (-ve: from right) (0)
// I: end index (-ve: from right) (X)
// → [start index, end index]const array = require("extra-array");
var x = [2, 4, 6, 8];
array.indexRange(x, 1);
// [1, 4]
array.indexRange(x, 1, -1);
// [1, 3]
array.indexRange(x, 1, -10);
// [1, 1]