meteor-sdk/src/classes/ddpReactiveDocument.ts

The aim of this library is to simplify the process of working with meteor server over DDP protocol using external JS environments

import { ddpOnChange } from './ddpOnChange.js';
import { ddpReactiveCollection } from "./ddpReactiveCollection";

/**
 * A reactive document class.
 * @constructor
 * @param {ddpReactiveCollection} ddpReactiveCollectionInstance - Instance of @see ddpReactiveCollection class.
 * @param {Object} [settings={preserve:false}] - Settings for reactive object. When preserve is true,
 * reactive object won't change when corresponding object is being deleted.
 */

export class ddpReactiveDocument<T> {
  private _ddpReactiveCollectionInstance: any;
  private _started: boolean;
  private readonly _data: {};
  private _tickers: any[];
  private _preserve: boolean;


  constructor(ddpReactiveCollectionInstance: ddpReactiveCollection<T>, settings: { preserve: any; } | null) {
    this._ddpReactiveCollectionInstance = ddpReactiveCollectionInstance;
    this._started = false;
    this._data = {};
    this._tickers = [];
    this._preserve = false;
    if (typeof settings === 'object' && settings !== null) this.settings(settings);
    this.start();
  }

  /**
   * Updates reactive object from local collection copies.
   * @private
   * @param {Object} newState - Document's new state.
   */
  _update<T>(newState: T) {
    if (newState) {
      //clean object
      Object.keys(this._data).forEach((key) => {
        // @ts-ignore
        delete this._data[key];
      });
      //assign new state
      Object.assign(this._data, newState);
    } else {
      // no object clean if not preserved
      if (!this._preserve) {
        Object.keys(this._data).forEach((key) => {
          // @ts-ignore
          delete this._data[key];
        });
      }
    }

    this._tickers.forEach((ticker) => {
      ticker(this.data());
    });
  }

  /**
   * Starts reactiveness for the document. This method is being called on instance creation.
   * @public
   */
  start() {
    if (!this._started) {
      this._update(this._ddpReactiveCollectionInstance.data()[0]);
      this._ddpReactiveCollectionInstance._activateReactiveObject(this);
      this._started = true;
    }
  }

  /**
   * Stops reactiveness for the document.
   * @public
   */
  stop() {
    if (this._started) {
      this._ddpReactiveCollectionInstance._deactivateReactiveObject(this);
      this._started = false;
    }
  }

  /**
   * Returns reactive document.
   * @public
   * @return {Object}
   */
  data() {
    return this._data as T;
  }

  /**
   * Runs a function every time a change occurs.
   * @param {Function} f - Function which recieves a new value at each change.
   * @public
   */
  onChange(f: {}) {
    const self = this as unknown as { [x: string]: any[] };
    return ddpOnChange(f, self, '_tickers');
  }

  /**
   * Change reactivity settings.
   * @param {Object} settings
   * @param {boolean} settings.preserve - When preserve is true,reactive object won't change when corresponding object is being deleted.
   * @public
   */
  settings({ preserve }: { preserve: boolean; }) {
    this._preserve = !!preserve;
  }
}