Hash

class HashTable {
  constructor(size){
    this.data = new Array(size);
    // this.data = [];
  }

  _hash(key) {
    let hash = 0;
    for (let i =0; i < key.length; i++){
        hash = (hash + key.charCodeAt(i) * i) % this.data.length
    }
    return hash;
  }

  set(key, value) {
    let address = this._hash(key);
    if (!this.data[address]) {
      this.data[address] = [];
    }
    this.data[address].push([key, value]);
    return this.data;
  }

  get(key){
    const address = this._hash(key);
    const currentBucket = this.data[address]
    if (currentBucket) {
      for(let i = 0; i < currentBucket.length; i++){
        if(currentBucket[i][0] === key) {
          return currentBucket[i][1]
        }
      }
    }
    return undefined;
  }
  
  keys(){
    const keysArray = [];
    console.log(this.data.length);
    for (let i = 0; i < this.data.length; i++){
      if(this.data[i]){
        keysArray.push(this.data[i][0][0])
      }
    }
    return keysArray;
  }
}

const myHashTable = new HashTable(50);
myHashTable.set('grapes', 10000)
myHashTable.set('grapes', 10000)
myHashTable.get('grapes')
myHashTable.set('apples', 9)
myHashTable.get('apples')
myHashTable.keys()


//  keys() {
//     if (!this.data.length) {
//       return undefined
//     }
//     let result = []
//     // loop through all the elements
//     for (let i = 0; i < this.data.length; i++) {
//         // if it's not an empty memory cell
//         if (this.data[i] && this.data[i].length) {
//           // but also loop through all the potential collisions
//           if (this.data.length > 1) {
//             for (let j = 0; j < this.data[i].length; j++) {
//               result.push(this.data[i][j][0])
//             }
//           } else {
//             result.push(this.data[i][0])
//           } 
//         }
//     }
//     return result; 
//   }