interface IntfKeyVal {
  (key: string, val: any): void
}

export class HashSet<T> {
  private items: { [key: string]: T }

  constructor() {
    this.items = {}
  }

  set(key: string, value: T): void {
    this.items[key] = value
  }

  delete(key: string): boolean {
    return delete this.items[key]
  }

  has(key: string): boolean {
    return key in this.items
  }

  get(key: string): T {
    return this.items[key]
  }

  len(): number {
    return Object.keys(this.items).length
  }

  forEach(f: IntfKeyVal) {
    for (let k in this.items) {
      if (this.items.hasOwnProperty(k)) {
        f(k, this.items[k])
      }
    }
  }
}