nly-adminlte-vue/dist/src/mixins/listen-on-window.js

nly adminlte3 components

import { arrayIncludes } from "../utils/array";
import { isBrowser } from "../utils/env";
import { EVENT_OPTIONS_NO_CAPTURE, eventOn, eventOff } from "../utils/events";
import { isString, isFunction } from "../utils/inspect";
import { keys } from "../utils/object";

const PROP = "$_nlya_windowHandlers_";

// @vue/component
export default {
  beforeCreate() {
    // Declare non-reactive property
    // Object of arrays, keyed by event name,
    // where value is an array of handlers
    this[PROP] = {};
  },
  beforeDestroy() {
    if (isBrowser) {
      const items = this[PROP];
      // Immediately delete this[PROP] to prevent the
      // listenOn/Off methods from running (which may occur
      // due to requestAnimationFrame delays)
      delete this[PROP];
      // Remove all registered event handlers
      keys(items).forEach(evtName => {
        const handlers = items[evtName] || [];
        handlers.forEach(handler =>
          eventOff(window, evtName, handler, EVENT_OPTIONS_NO_CAPTURE)
        );
      });
    }
  },
  methods: {
    listenWindow(on, evtName, handler) {
      on
        ? this.listenOnWindow(evtName, handler)
        : this.listenOffWindow(evtName, handler);
    },
    listenOnWindow(evtName, handler) {
      if (isBrowser && this[PROP] && isString(evtName) && isFunction(handler)) {
        this[PROP][evtName] = this[PROP][evtName] || [];
        if (!arrayIncludes(this[PROP][evtName], handler)) {
          this[PROP][evtName].push(handler);
          eventOn(window, evtName, handler, EVENT_OPTIONS_NO_CAPTURE);
        }
      }
    },
    listenOffWindow(evtName, handler) {
      if (isBrowser && this[PROP] && isString(evtName) && isFunction(handler)) {
        eventOff(window, evtName, handler, EVENT_OPTIONS_NO_CAPTURE);
        this[PROP][evtName] = (this[PROP][evtName] || []).filter(
          h => h !== handler
        );
      }
    }
  }
};