JS String To Hash

<div>
  <input type="text" id="myString">
  <button onClick="hash()">
  Generate Hash
  </button>
</div>
<div>
  <span>Result: </span>
  <span id="myHash"></span>
</div>

const hash = () => {
	const myString = document.getElementById('myString').value;
  let myHash = myString.hashCode();
  document.getElementById('myHash').innerHTML = myHash;	
} 

// as prototype method
String.prototype.hashCode = function(){
	var hash = 0;
	if (this.length == 0) return hash;
	for (i = 0; i < this.length; i++) {
		char = this.charCodeAt(i);
		hash = ((hash<<5)-hash)+char;
		hash = hash & hash; // Convert to 32bit integer
	}
	return hash;
}

// alternative: as function
hashCode = (s) => {
  return s.split('').reduce( (a, b) => {
    a = (( a << 5 ) - a ) + b.charCodeAt(0);
    return a & a;
  }, 0);    
}