hash-bc/src/Hash.js

A easy Hash Table for JavaScript

const HashItem = require('./HashItem');

class Hash {
  constructor(length) {
    this.data = new Array(length);
    this.length = length || 0;
  }

  _hashHandler(key) {
    let counter = 0;
    for (let i = 0; i < key.length; i++) {
      counter += key.charCodeAt(i);
    }

    return counter % this.length;
  }

  setItem(key, value) {
    const position = this._hashHandler(key);
    const item = new HashItem(key, value);

    if (this.data[position] !== undefined) {
      const existsTheSameItem = this.data[position].filter((value) => value.key === key)[0];
      if (!existsTheSameItem) {
        this.data[position].push(item);
      } else {
        console.warn(`The key ${key} already exist`);
        return {
          completed: false,
          item: item,
        };
      }
    } else {
      this.data[position] = [item];
    }
    return {
      completed: true,
      item: item,
    };
  }

  getItem(key) {
    const position = this._hashHandler(key);
    if (typeof value === 'object') {
      return this.data[position].filter((value) => value.key === key) || undefined;
    } else {
      console.error(`The key: ${key} doesn't exist`);
      return undefined;
    }
  }

  getKeys() {
    const keys = [];
    this.data.map((value) => {
      if (typeof value === 'object') {
        value.map((value) => keys.push(value.key));
      }
    });

    return keys;
  }

  deleteItem(key) {
    const position = this._hashHandler(key);

    if (typeof this.data[position] === 'object') {
      this.data[position].map((value, index) => {
        if (value.key === key) {
          return this.data[position].splice(index, 1);
        }
      });
    } else {
      console.error(`The key: ${key} doesn't exist`);
      return undefined;
    }
  }
}

module.exports = Hash;