discordeno/utils/collection.ts

import { chooseRandom } from "./utils.ts";

export default class Collection<K, V> extends Map<K, V> {
  array() {
    return [...this.values()];
  }

  first() {
    return this.values().next().value;
  }

  last() {
    return [...this.values()][this.size - 1];
  }

  random() {
    return chooseRandom([...this.values()]);
  }

  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<T>(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<T>(
    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;
  }
}