hash map

hash-map.js

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

class HashMap {
  constructor(size) {
		this.buckets = Array.from({ length: size }, () => []);
    this.size = size
  }
  
  _hash(key) {
  	return Math.abs(key.hashCode()) % this.size;
  }
  
  put(key, value) {
  	const index = this._hash(key);
    const bucket = this.buckets[index];
    
    const has = bucket.some((item) => Object.keys(item).includes(key));

    if (has) return;
    
    bucket.push({ [key]: value });
  }
}

const hm = new HashMap(10);

hm.put('valter', 20)
/* duplicated */
hm.put('valter', 20)
hm.put('retlav', 20)
hm.put('Roberto', 30)

console.log(hm.buckets)