MaxGraey_search_bytes_solution

function isSubset(haystack, needle) {
    return new Promise(function(resolve, reject) {
        let n = haystack.length;
        let m = needle.length;
        for (let i = 0, j = 0; i < n; i++) {
            if (haystack[i] === needle[j++]) {
                if (j >= m) resolve("Present");
            } else j = 0
        }
        resolve("Absent");
    });
}
var buffer_1 = new ArrayBuffer(50000);
var buffer_2 = new ArrayBuffer(1000000);
var needle = new Uint8Array(buffer_1);
var haystack = new Uint8Array(buffer_2);
needle.fill(111);
haystack.fill(222);
if (needle_length < 1 || needle_length > haystack_length) {
    alert("Needle length must be greater than zero and less than haystack length");
} else {
    isSubset(haystack, needle)
        .then(function(result) {
            console.log("Result: " + result);
        })
        .catch(function() {
            console.log("Error");
        });
}

Inspired by this Tweet https://twitter.com/MaxGraey/status/1329915996342259720