1/**
2 * Calculate a 32 bit FNV-1a hash
3 * Found here: https://gist.github.com/vaiorabbit/5657561
4 * Ref.: http://isthe.com/chongo/tech/comp/fnv/
5 *
6 * @param {string} str the input value
7 * @param {boolean} [asString=false] set to true to return the hash value as 
8 *     8-digit hex string instead of an integer
9 * @param {integer} [seed] optionally pass the hash of the previous chunk
10 * @returns {integer | string}
11 */
12function hashFnv32a(str, asString, seed) {
13    /*jshint bitwise:false */
14    var i, l,
15        hval = (seed === undefined) ? 0x811c9dc5 : seed;
16
17    for (i = 0, l = str.length; i < l; i++) {
18        hval ^= str.charCodeAt(i);
19        hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
20    }
21    if( asString ){
22        // Convert to 8 digit hex string
23        return ("0000000" + (hval >>> 0).toString(16)).substr(-8);
24    }
25    return hval >>> 0;
26}

1function hashFnv32a(str, asString, seed) {
2    /*jshint bitwise:false */
3    var i, l,
4        hval = (seed === undefined) ? 0x811c9dc5 : seed;
5
6    for (i = 0, l = str.length; i < l; i++) {
7        hval ^= str.charCodeAt(i);
8        hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24);
9    }
10    if( asString ){
11        // Convert to 8 digit hex string
12        return ("0000000" + (hval >>> 0).toString(16)).substr(-8);
13    }
14    return hval >>> 0;
15}

1function hashCode(str) {
2  return str.split('').reduce((prevHash, currVal) =>
3    (((prevHash << 5) - prevHash) + currVal.charCodeAt(0))|0, 0);
4}
5
6// Test
7console.log("hashCode(\"Hello!\"): ", hashCode('Hello!'));