Hashtable.js

var hash = (string, max) => {
  var hash = 0;
  for (var i = 0; i < string.length; i++) {
    hash += string.charCodeAt(i);
  }
  return hash % max;
};

let HashTable = function() {
  let storage = [];
  const storageLimit = 4; // Number of buckets in the array
  this.print = function() {
    console.log(storage);
  }

  this.add = function(key, value) {
    var index = hash(key, storageLimit);
    if(storage[index] === undefined) {
      storage[index]= [
        [key, value]
      ];
    } else {
      var inserted = false;
      for (var i = 0; i < storage[index].length; i++) {
        if (storage[index][i][0] === key) {
          storage[index][i][1] = value;
          inserted = true;
        }
      }
      if (inserted === false) {
        storage[index].push([key, value]);
      }
    }
  };

  this.remove = function(key) {
    var index = hash(key, storageLimit);
    if (storage[index].length === 1 && storage[index][0][0] === key) {
      delete storage[index];
    } else {
      for (var i = 0; i < storage[index]; i++) {
        if (storage[index][i][0] === key) {
          delete storage[index][i];
        }
      }
    }
  };

  this.lookup = function(key) {
    var index = hash(key, storageLimit);
    if (storage[index] === undefined) {
      return undefined;
    } else {
      for (var i= 0; i < storage [index].length; i++) {
        if (storage[index][i][0] === key) {
          return storage[index][i][1];
        }
      }
    }
  };

};

//This Hash table will return a number between 0 and 9. as we have number 10 as
//the max number of buckets
console.log(hash('beau', 10));
console.log(hash('quincy', 10));

let ht = new HashTable();
ht.add('beau', 'person');
ht.add('fido', 'dog');
ht.add('rex', 'dinosaur');
ht.add('tux', 'penguin');
console.log(ht.lookup('tux'));
ht.print();