In Javascript, create a hash table from scratch.

hashtable.js

class HashTable {
  constructor(size = 53) {
    this.buckets = Array.from({ length: size }, () => new Map()); // Use Map instead of arrays
    this.size = size;
  }

  _hash = (key) =>
    [...key].reduce((acc, char) => (acc + char.charCodeAt(0) * 23) % this.size, 0);

  set(key, value) {
    this.buckets[this._hash(key)].set(key, value); // Directly store in Map
  }

  get = (key) => this.buckets[this._hash(key)].get(key);

  delete(key) {
    return this.buckets[this._hash(key)].delete(key);
  }

  keys = () =>
    this.buckets.flatMap((bucket) => [...bucket.keys()]);

  values = () =>
    this.buckets.flatMap((bucket) => [...bucket.values()]);
}

// Example usage:
const ht = new HashTable();
ht.set("name", "Alice");
ht.set("age", 25);
ht.set("occupation", "Engineer");

console.log(ht.get("name")); // Alice
console.log(ht.get("age")); // 25
console.log(ht.delete("age")); // true
console.log(ht.get("age")); // undefined
console.log(ht.keys()); // ["name", "occupation"]
console.log(ht.values()); // ["Alice", "Engineer"]

Map provides O(1) average time complexity for insertions, lookups, and deletions.

Set is great for unique keys, but a hash table stores key-value pairs.

Set could be useful for a unique key store but wouldn't replace Map in this implementation.

Set wouldn’t be useful here since we need key-value storage, not just unique keys.