capivarajs/src/core/observer/index.ts

Um framework para criação de componentes.

import { Polyfill } from './polyfill';
import { Util } from './util';

export namespace Observe {

  const watchers = new WeakMap();

  export function observe(obj, handler) {
    if (!obj) {
      return;
    }
    if (!watchers.has(obj)) {
      watchers.set(obj, [handler]);
      this.create(obj, (changes) => {
        (watchers.get(obj) || []).forEach((watcher) => {
          watcher(changes);
        });
      });
    } else {
      const handlers = watchers.get(obj);
      handlers.push(handler);
      watchers.set(obj, handlers);
    }
  }

  export function unobserve(obj) {
    this.destroy(obj);
    watchers.delete(obj);
  }

  export function create(obj, handler, objCreated = []) {
    if (obj && obj.__observer__) {
      return false;
    }
    objCreated.push(obj);
    let props = Util.keys(obj);
    const propsL = props.length;
    Polyfill.setDirtyCheck(obj, 50, updateProperties);
    for (let i = 0; i < propsL; i++) {
      if (Object.prototype.toString.call(obj[props[i]]) === '[object Object]' || Array.isArray(obj[props[i]])) {
        if (objCreated.indexOf(obj[props[i]]) === -1 && !obj[props[i]].__observer__) {
          this.create(obj[props[i]], handler, objCreated);
        }
      } else {
        Polyfill.watchProperty(obj, props[i], handler);
      }
    }
    function updateProperties() {
      if (!Util.compare(props, Util.keys(obj))) {
        Polyfill.updateProperties(Util.diff(props, Util.keys(obj)), obj, handler);
        props = Util.keys(obj);
      }
    }
  }

  export function destroy(obj, objDestroyed = []) {
    if (!obj || !obj.__observer__) {
      return false;
    }

    objDestroyed.push(obj);
    const props = Object.keys(obj),
      propsL = props.length;

    Polyfill.clearDirtyCheck(obj);

    for (let i = 0; i < propsL; i++) {
      if (Object.prototype.toString.call(obj[props[i]]) === '[object Object]' || Array.isArray(obj[props[i]])) {
        if (objDestroyed.indexOf(obj[props[i]]) === -1 && obj[props[i]].__observer__) {
          this.destroy(obj[props[i]], objDestroyed);
        }
      } else {
        Polyfill.unWatchProperty(obj, props[i]);
      }
    }
  }

}