@std/bytes@0.215.0

Returns the index of the first occurrence of the needle array in the source array, or -1 if it is not present.

A start index can be specified as the third argument that begins the search at that given index. The start index defaults to the start of the array.

The complexity of this function is O(source.length * needle.length).

import { indexOfNeedle } from "@std/bytes/index_of_needle";
const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
const needle = new Uint8Array([1, 2]);
console.log(indexOfNeedle(source, needle)); // 1
console.log(indexOfNeedle(source, needle, 2)); // 3