export class Collection extends Map { maxSize: number | undefined; constructor(entries?: (readonly (readonly [K, V])[] | null) | Map, options?: CollectionOptions) { super(entries ?? []); this.maxSize = options?.maxSize; } set(key: K, value: V) { // When this collection is maxSized make sure we can add first if ((this.maxSize || this.maxSize === 0) && this.size >= this.maxSize) { return this; } return super.set(key, value); } forceSet(key: K, value: V) { return super.set(key, value); } array() { return [...this.values()]; } /** Retrieve the value of the first element in this collection */ first(): V | undefined { return this.values().next().value; } last(): V | undefined { return [...this.values()][this.size - 1]; } random(): V | undefined { const array = [...this.values()]; return array[Math.floor(Math.random() * array.length)]; } find(callback: (value: V, key: K) => boolean) { for (const key of this.keys()) { const value = this.get(key)!; if (callback(value, key)) return value; } // If nothing matched return; } filter(callback: (value: V, key: K) => boolean) { const relevant = new Collection(); this.forEach((value, key) => { if (callback(value, key)) relevant.set(key, value); }); return relevant; } map(callback: (value: V, key: K) => T) { const results = []; for (const key of this.keys()) { const value = this.get(key)!; results.push(callback(value, key)); } return results; } some(callback: (value: V, key: K) => boolean) { for (const key of this.keys()) { const value = this.get(key)!; if (callback(value, key)) return true; } return false; } every(callback: (value: V, key: K) => boolean) { for (const key of this.keys()) { const value = this.get(key)!; if (!callback(value, key)) return false; } return true; } reduce(callback: (accumulator: T, value: V, key: K) => T, initialValue?: T): T { let accumulator: T = initialValue!; for (const key of this.keys()) { const value = this.get(key)!; accumulator = callback(accumulator, value, key); } return accumulator; } } export interface CollectionOptions { maxSize?: number; }