hashtable.js

class Node {
	constructor(key, value) {
		this.key = key;
		this.value = value;
		this.next = null;
	}
}

class Table {
	constructor(size) {
		this.cells = new Array(size);
	}

	hash(key) {
		let total = 0;

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

		return total % this.cells.length;
	}

	insert(key, value) {
		const hash = this.hash(key);

		if (!this.cells[hash]) {
			this.cells[hash] = new Node(key, value);
		} else if (this.cells[hash].key === key) {
			this.cells[hash].value = value;
		} else {
			let node = this.cells[hash];

			while (node.next) {
				if (node.next.key === key) {
					node.next.value = value;
					return;
				}

				node = node.next;
			}

			node.next = new Node(key, value);
		}
	}

	get(key) {
		const hash = this.hash(key);
		if (!this.cells[hash]) {
      return null; 
    }

    let node = this.cells[hash];

    while (node) {
      if (node.key === key) {
        return node.value;
      }

      node = node.next;
    }

    return null;
	}

	getAll() {
		const table = [];

		for (let i = 0; i < this.cells.length; i++) {
			const cell = [];
			let node = this.cells[i];

			while (node) {
				cell.push(node.value);
				node = node.next;
			}

			table.push(cell);
		}

		return table;
	}
}

const table = new Table(5);
table.insert("baa", 1);
table.insert("aba", 2);
table.insert("aba", 3);
table.insert("aac", 4);
table.insert("aac", 5);

console.log(table.get('aac'));
console.log(table.get('baa'));