hash-table-example.js

const stringHash = require("string-hash");

module.exports = class MyHashTable {
  constructor(numberOfBucket) {
    this.numberOfBucket = parseInt(numberOfBucket, 10);
    this.hashTable = new Array(this.numberOfBucket);
  }
  get(key) {
    key = '' + key;
    const hashTableIndex = this.getHashTableIndex(key);
    const bucket = this.hashTable[hashTableIndex] || [];
    const bucketLength = bucket.length;
    for (let i=0; i<bucketLength; i++) {
      const data = bucket[i];
      if (data[0] === key) {
        return data[1];
      }
    }
  }
  set(key, value) {
    key = '' + key;
    const hashTableIndex = this.getHashTableIndex(key);
    if (!this.hashTable[hashTableIndex]) {
      this.hashTable[hashTableIndex] = [];
    }
    this.hashTable[hashTableIndex].push([key, value]);
  }
  getHashTableIndex(key){
    const hash = stringHash(key);
    return hash % this.numberOfBucket;
  }
}