@push.rocks/lik/ts/classes.objectmap.ts

Provides a collection of lightweight helpers and utilities for Node.js projects.

import * as plugins from './classes.plugins.js';
import { FastMap } from './classes.fastmap.js';

export const uni = (prefix: string = 'uni') => {
  return `${prefix}xxxxxxxxxxx`.replace(/[xy]/g, (c) => {
    const r = (Math.random() * 16) | 0;
    const v = c === 'x' ? r : (r & 0x3) | 0x8;
    return v.toString(16);
  });
};

export interface IObjectmapForEachFunction<T> {
  (itemArg: T): void;
}

export interface IObjectmapFindFunctionSync<T> {
  (itemArg: T): boolean;
}

export interface IObjectmapFindFunction<T> {
  (itemArg: T): Promise<boolean>;
}

export interface IObjectMapEventData<T> {
  operation: 'add' | 'remove';
  payload: T;
}

/**
 * allows keeping track of objects
 */
export class ObjectMap<T> {
  private fastMap = new FastMap<T>();
  private reverseMap = new Map<T, string>();

  // events
  public eventSubject = new plugins.smartrx.rxjs.Subject<IObjectMapEventData<T>>();

  /**
   * returns a new instance
   */
  constructor() {
    // nothing here
  }

  /**
   * the number of objects in the map
   */
  public get length(): number {
    return this.fastMap.size;
  }

  /**
   * adds an object mapped to a string
   * the string must be unique
   */
  addMappedUnique(uniqueKeyArg: string, objectArg: T) {
    this.fastMap.addToMap(uniqueKeyArg, objectArg);
    this.reverseMap.set(objectArg, uniqueKeyArg);
  }

  /**
   * fastest way to get an object from the map
   * @param uniqueKey
   */
  public getMappedUnique(uniqueKeyArg: string) {
    return this.fastMap.getByKey(uniqueKeyArg);
  }

  /**
   * remove key
   * @param functionArg
   */
  public removeMappedUnique(uniqueKey: string): T {
    const object = this.fastMap.removeFromMap(uniqueKey);
    if (object !== undefined) {
      this.reverseMap.delete(object);
      this.eventSubject.next({
        operation: 'remove',
        payload: object,
      });
    }
    return object;
  }

  /**
   * add object to Objectmap
   * returns the key for the object (existing or new)
   */
  public add(objectArg: T): string {
    const existingKey = this.reverseMap.get(objectArg);
    if (existingKey !== undefined) {
      return existingKey;
    }

    const uniqueKey = uni('key');
    this.addMappedUnique(uniqueKey, objectArg);
    this.eventSubject.next({
      operation: 'add',
      payload: objectArg,
    });
    return uniqueKey;
  }

  /**
   * like .add but adds an whole array of objects
   */
  public addArray(objectArrayArg: T[]) {
    for (const item of objectArrayArg) {
      this.add(item);
    }
  }

  /**
   * check if object is in Objectmap
   */
  public checkForObject(objectArg: T): boolean {
    return this.reverseMap.has(objectArg);
  }

  /**
   * get key for object
   */
  public getKeyForObject(objectArg: T): string | null {
    return this.reverseMap.get(objectArg) ?? null;
  }

  /**
   * find object
   */
  public async find(findFunction: IObjectmapFindFunction<T>): Promise<T> {
    return this.fastMap.find(findFunction);
  }

  public findSync(findFunction: IObjectmapFindFunctionSync<T>): T {
    for (const keyArg of this.fastMap.getKeys()) {
      if (findFunction(this.fastMap.getByKey(keyArg))) {
        return this.getMappedUnique(keyArg);
      }
    }
  }

  /**
   * finds a specific element and then removes it
   */
  public async findOneAndRemove(findFunction: IObjectmapFindFunction<T>): Promise<T> {
    const foundElement = await this.find(findFunction);
    if (foundElement) {
      this.remove(foundElement);
    }
    return foundElement;
  }
  public findOneAndRemoveSync(findFunction: IObjectmapFindFunctionSync<T>): T {
    const foundElement = this.findSync(findFunction);
    if (foundElement) {
      this.remove(foundElement);
    }
    return foundElement;
  }

  /**
   * run function for each item in Objectmap
   */
  public async forEach(functionArg: IObjectmapForEachFunction<T>) {
    for (const keyArg of this.fastMap.getKeys()) {
      await functionArg(this.fastMap.getByKey(keyArg));
    }
  }

  /**
   * gets an object in the Observablemap and removes it, so it can't be retrieved again
   */
  public getOneAndRemove(): T {
    const keys = this.fastMap.getKeys();
    if (keys.length === 0) {
      return null;
    } else {
      const keyToUse = keys[0];
      const removedItem = this.fastMap.removeFromMap(keyToUse);
      this.reverseMap.delete(removedItem);
      this.eventSubject.next({
        operation: 'remove',
        payload: removedItem,
      });
      return removedItem;
    }
  }

  /**
   * returns a cloned array of all the objects currently in the Objectmap
   */
  public getArray(): T[] {
    return this.fastMap.values();
  }

  /**
   * check if Objectmap ist empty
   */
  public isEmpty(): boolean {
    return this.fastMap.size === 0;
  }

  /**
   * remove object from Objectmap
   */
  public remove(objectArg: T): T {
    const keyArg = this.reverseMap.get(objectArg);
    if (keyArg !== undefined) {
      const removedObject = this.fastMap.removeFromMap(keyArg);
      this.reverseMap.delete(removedObject);
      this.eventSubject.next({
        operation: 'remove',
        payload: removedObject,
      });
      return removedObject;
    }
    return null;
  }

  /**
   * wipe Objectmap
   */
  public wipe() {
    const keys = this.fastMap.getKeys();
    for (const keyArg of keys) {
      const removedObject = this.fastMap.removeFromMap(keyArg);
      this.reverseMap.delete(removedObject);
      this.eventSubject.next({
        operation: 'remove',
        payload: removedObject,
      });
    }
  }

  /**
   * returns a new Objectmap that includes
   */
  public concat(objectMapArg: ObjectMap<T>) {
    const concattedObjectMap = new ObjectMap<T>();
    concattedObjectMap.fastMap.addAllFromOther(this.fastMap);
    concattedObjectMap.fastMap.addAllFromOther(objectMapArg.fastMap);
    // rebuild reverse map for the concatenated map
    for (const key of concattedObjectMap.fastMap.getKeys()) {
      concattedObjectMap.reverseMap.set(concattedObjectMap.fastMap.getByKey(key), key);
    }
    return concattedObjectMap;
  }

  /**
   * tries to merge another Objectmap
   * Note: uniqueKeyCollisions will cause overwrite
   * @param objectMapArg
   */
  public addAllFromOther(objectMapArg: ObjectMap<T>) {
    this.fastMap.addAllFromOther(objectMapArg.fastMap);
    // rebuild reverse map
    for (const key of objectMapArg.fastMap.getKeys()) {
      this.reverseMap.set(objectMapArg.fastMap.getByKey(key), key);
    }
  }

  public map<U>(fn: (item: T) => U): U[] {
    return this.getArray().map(fn);
  }

  public filter(fn: (item: T) => boolean): T[] {
    return this.getArray().filter(fn);
  }

  public reduce<U>(fn: (acc: U, item: T) => U, initial: U): U {
    return this.getArray().reduce(fn, initial);
  }

  public [Symbol.iterator](): Iterator<T> {
    return this.getArray()[Symbol.iterator]();
  }

  /**
   * destroys the ObjectMap, completing the eventSubject and clearing all entries
   */
  public destroy() {
    this.wipe();
    this.reverseMap.clear();
    this.eventSubject.complete();
  }
}