ember-source/dist/prod/packages/shared-chunks/events-DYrYz3V8.js

A JavaScript framework for creating ambitious web applications

import { meta, peekMeta } from '../@ember/-internals/meta/lib/meta.js';
import { a as setListeners } from './super-BBBjgF69.js';

/**
@module @ember/object
*/


/*
  The event system uses a series of nested hashes to store listeners on an
  object. When a listener is registered, or when an event arrives, these
  hashes are consulted to determine which target and action pair to invoke.

  The hashes are stored in the object's meta hash, and look like this:

      // Object's meta hash
      {
        listeners: {       // variable name: `listenerSet`
          "foo:change": [ // variable name: `actions`
            target, method, once
          ]
        }
      }

*/

/**
  Add an event listener

  @method addListener
  @static
  @for @ember/object/events
  @param obj
  @param {String} eventName
  @param {Object|Function} target A target object or a function
  @param {Function|String} method A function or the name of a function to be called on `target`
  @param {Boolean} once A flag whether a function should only be called once
  @public
*/
function addListener(obj, eventName, target, method, once, sync = true) {
  if (!method && 'function' === typeof target) {
    method = target;
    target = null;
  }
  meta(obj).addToListeners(eventName, target, method, once === true, sync);
}

/**
  Remove an event listener

  Arguments should match those passed to `addListener`.

  @method removeListener
  @static
  @for @ember/object/events
  @param obj
  @param {String} eventName
  @param {Object|Function} target A target object or a function
  @param {Function|String} method A function or the name of a function to be called on `target`
  @public
*/
function removeListener(obj, eventName, targetOrFunction, functionOrName) {
  let target, method;
  if (typeof targetOrFunction === 'object') {
    target = targetOrFunction;
    method = functionOrName;
  } else {
    target = null;
    method = targetOrFunction;
  }
  let m = meta(obj);
  m.removeFromListeners(eventName, target, method);
}

/**
  Send an event. The execution of suspended listeners
  is skipped, and once listeners are removed. A listener without
  a target is executed on the passed object. If an array of actions
  is not passed, the actions stored on the passed object are invoked.

  @method sendEvent
  @static
  @for @ember/object/events
  @param obj
  @param {String} eventName
  @param {Array} params Optional parameters for each listener.
  @return {Boolean} if the event was delivered to one or more actions
  @public
*/
function sendEvent(obj, eventName, params, actions, _meta) {
  if (actions === undefined) {
    let meta = _meta === undefined ? peekMeta(obj) : _meta;
    actions = meta !== null ? meta.matchingListeners(eventName) : undefined;
  }
  if (actions === undefined || actions.length === 0) {
    return false;
  }
  for (let i = actions.length - 3; i >= 0; i -= 3) {
    // looping in reverse for once listeners
    let target = actions[i];
    let method = actions[i + 1];
    let once = actions[i + 2];
    if (!method) {
      continue;
    }
    if (once) {
      removeListener(obj, eventName, target, method);
    }
    if (!target) {
      target = obj;
    }
    let type = typeof method;
    if (type === 'string' || type === 'symbol') {
      method = target[method];
    }
    method.apply(target, params);
  }
  return true;
}

/**
  @public
  @method hasListeners
  @static
  @for @ember/object/events
  @param obj
  @param {String} eventName
  @return {Boolean} if `obj` has listeners for event `eventName`
*/
function hasListeners(obj, eventName) {
  let meta = peekMeta(obj);
  if (meta === null) {
    return false;
  }
  let matched = meta.matchingListeners(eventName);
  return matched !== undefined && matched.length > 0;
}

/**
  Define a property as a function that should be executed when
  a specified event or events are triggered.

  ``` javascript
  import EmberObject from '@ember/object';
  import { on } from '@ember/object/evented';
  import { sendEvent } from '@ember/object/events';

  let Job = EmberObject.extend({
    logCompleted: on('completed', function() {
      console.log('Job completed!');
    })
  });

  let job = Job.create();

  sendEvent(job, 'completed'); // Logs 'Job completed!'
 ```

  @method on
  @static
  @for @ember/object/evented
  @param {String} eventNames*
  @param {Function} func
  @return {Function} the listener function, passed as last argument to on(...)
  @public
*/
function on(...args) {
  let func = args.pop();
  let events = args;
  setListeners(func, events);
  return func;
}

export { addListener as a, hasListeners as h, on as o, removeListener as r, sendEvent as s };