Simple Tuple map experiment in TS

tuple-map.ts

type Tuple = [unknown, unknown];

export class TupleMap<T> implements Map<Tuple, T> {
  public [Symbol.iterator](): IterableIterator<[Tuple, T]> {
    throw new Error("Method not implemented.");
  }

  public keys(): IterableIterator<Tuple> {
    throw new Error("Method not implemented.");
  }
  public values(): IterableIterator<T> {
    throw new Error("Method not implemented.");
  }

  public [Symbol.toStringTag]: string;
  private readonly aMap: Map<string, T> = new Map<string, T>();

  public set(aKey: Tuple, aValue: T): this {
    this.aMap.set(JSON.stringify(aKey), aValue);

    return this;
  }

  public get(aKey: Tuple): T | undefined {
    return this.aMap.get(JSON.stringify(aKey));
  }

  public clear(): void {
    return this.aMap.clear();
  }

  public delete(aKey: Tuple): boolean {
    return this.aMap.delete(JSON.stringify(aKey));
  }

  public forEach(
    _: (value: T, key: Tuple, map: Map<Tuple, T>) => void,
    _1?: unknown,
  ): void {
    throw new Error("Method not implemented");
  }

  public has(aKey: Tuple): boolean {
    return this.aMap.has(JSON.stringify(aKey));
  }

  public get size(): number {
    return this.aMap.size;
  }

  public entries(): IterableIterator<[Tuple, T]> {
    throw new Error("Method not implemented");
  }
}