SyntheticEvent.js — react Source File

Source Code

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

/* eslint valid-typeof: 0 */

import assign from 'shared/assign';

const EVENT_POOL_SIZE = 10;

/**
 * @interface Event
 * @see http://www.w3.org/TR/DOM-Level-3-Events/
 */
const EventInterface = {
  type: null,
  target: null,
  // currentTarget is set when dispatching; no use in copying it here
  currentTarget: function () {
    return null;
  },
  eventPhase: null,
  bubbles: null,
  cancelable: null,
  timeStamp: function (event) {
    return event.timeStamp || Date.now();
  },
  defaultPrevented: null,
  isTrusted: null,
};

function functionThatReturnsTrue() {
  return true;
}

function functionThatReturnsFalse() {
  return false;
}

/**
 * Synthetic events are dispatched by event plugins, typically in response to a
 * top-level event delegation handler.
 *
 * These systems should generally use pooling to reduce the frequency of garbage
 * collection. The system should check `isPersistent` to determine whether the
 * event should be released into the pool after being dispatched. Users that
 * need a persisted event should invoke `persist`.
 *
 * Synthetic events (and subclasses) implement the DOM Level 3 Events API by
 * normalizing browser quirks. Subclasses do not necessarily have to implement a
 * DOM interface; custom application-specific events can also subclass this.
 *
 * @param {object} dispatchConfig Configuration used to dispatch this event.
 * @param {*} targetInst Marker identifying the event target.
 * @param {object} nativeEvent Native browser event.
 * @param {DOMEventTarget} nativeEventTarget Target node.
 */
// ... (288 more lines)