freifunk-app/node_modules/event-target-shim/lib/event-wrapper.js

/**
 * @author Toru Nagashima
 * @copyright 2015 Toru Nagashima. All rights reserved.
 * See LICENSE file in root directory for full license.
 */

"use strict";

//-----------------------------------------------------------------------------
// Requirements
//-----------------------------------------------------------------------------

var createUniqueKey = require("./commons").createUniqueKey;

//-----------------------------------------------------------------------------
// Constsnts
//-----------------------------------------------------------------------------

/**
 * The key of the flag which is turned on by `stopImmediatePropagation` method.
 *
 * @type {symbol|string}
 * @private
 */
var STOP_IMMEDIATE_PROPAGATION_FLAG =
    createUniqueKey("stop_immediate_propagation_flag");

/**
 * The key of the flag which is turned on by `preventDefault` method.
 *
 * @type {symbol|string}
 * @private
 */
var CANCELED_FLAG = createUniqueKey("canceled_flag");

/**
 * The key of the original event object.
 *
 * @type {symbol|string}
 * @private
 */
var ORIGINAL_EVENT = createUniqueKey("original_event");

/**
 * Method definitions for the event wrapper.
 *
 * @type {object}
 * @private
 */
var wrapperPrototypeDefinition = Object.freeze({
    stopPropagation: Object.freeze({
        value: function stopPropagation() {
            var e = this[ORIGINAL_EVENT];
            if (typeof e.stopPropagation === "function") {
                e.stopPropagation();
            }
        },
        writable: true,
        configurable: true
    }),

    stopImmediatePropagation: Object.freeze({
        value: function stopImmediatePropagation() {
            this[STOP_IMMEDIATE_PROPAGATION_FLAG] = true;

            var e = this[ORIGINAL_EVENT];
            if (typeof e.stopImmediatePropagation === "function") {
                e.stopImmediatePropagation();
            }
        },
        writable: true,
        configurable: true
    }),

    preventDefault: Object.freeze({
        value: function preventDefault() {
            if (this.cancelable === true) {
                this[CANCELED_FLAG] = true;
            }

            var e = this[ORIGINAL_EVENT];
            if (typeof e.preventDefault === "function") {
                e.preventDefault();
            }
        },
        writable: true,
        configurable: true
    }),

    defaultPrevented: Object.freeze({
        get: function defaultPrevented() { return this[CANCELED_FLAG]; },
        enumerable: true,
        configurable: true
    })
});

//-----------------------------------------------------------------------------
// Public Interface
//-----------------------------------------------------------------------------

exports.STOP_IMMEDIATE_PROPAGATION_FLAG = STOP_IMMEDIATE_PROPAGATION_FLAG;

/**
 * Creates an event wrapper.
 *
 * We cannot modify several properties of `Event` object, so we need to create the wrapper.
 * Plus, this wrapper supports non `Event` objects.
 *
 * @param {Event|{type: string}} event - An original event to create the wrapper.
 * @param {EventTarget} eventTarget - The event target of the event.
 * @returns {Event} The created wrapper. This object is implemented `Event` interface.
 * @private
 */
exports.createEventWrapper = function createEventWrapper(event, eventTarget) {
    var timeStamp = (
        typeof event.timeStamp === "number" ? event.timeStamp : Date.now()
    );
    var propertyDefinition = {
        type: {value: event.type, enumerable: true},
        target: {value: eventTarget, enumerable: true},
        currentTarget: {value: eventTarget, enumerable: true},
        eventPhase: {value: 2, enumerable: true},
        bubbles: {value: Boolean(event.bubbles), enumerable: true},
        cancelable: {value: Boolean(event.cancelable), enumerable: true},
        timeStamp: {value: timeStamp, enumerable: true},
        isTrusted: {value: false, enumerable: true}
    };
    propertyDefinition[STOP_IMMEDIATE_PROPAGATION_FLAG] = {value: false, writable: true};
    propertyDefinition[CANCELED_FLAG] = {value: false, writable: true};
    propertyDefinition[ORIGINAL_EVENT] = {value: event};

    // For CustomEvent.
    if (typeof event.detail !== "undefined") {
        propertyDefinition.detail = {value: event.detail, enumerable: true};
    }

    return Object.create(
        Object.create(event, wrapperPrototypeDefinition),
        propertyDefinition
    );
};