frc-ui/es/socket/emitter.js

React Web UI

"use strict";
/**
 * Expose `Emitter`.
 */
// @ts-ignore
if (typeof module !== 'undefined') {
    // @ts-ignore
    module.exports = Emitter;
}
/**
 * Initialize a new `Emitter`.
 *
 * @api public
 */
function Emitter(obj) {
    if (obj)
        return mixin(obj);
}
/**
 * Mixin the emitter properties.
 *
 * @param {Object} obj
 * @return {Object}
 * @api private
 */
function mixin(obj) {
    for (var key in Emitter.prototype) {
        obj[key] = Emitter.prototype[key];
    }
    return obj;
}
/**
 * Listen on the given `event` with `fn`.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */
Emitter.prototype.on = Emitter.prototype.addEventListener = function (event, fn) {
    this._callbacks = this._callbacks || {};
    (this._callbacks['$' + event] = this._callbacks['$' + event] || []).push(fn);
    return this;
};
/**
 * Adds an `event` listener that will be invoked a single
 * time then automatically removed.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */
Emitter.prototype.once = function (event, fn) {
    function on() {
        this.off(event, on);
        fn.apply(this, arguments);
    }
    on.fn = fn;
    this.on(event, on);
    return this;
};
/**
 * Remove the given callback for `event` or all
 * registered callbacks.
 *
 * @param {String} event
 * @param {Function} fn
 * @return {Emitter}
 * @api public
 */
Emitter.prototype.off = Emitter.prototype.removeListener = Emitter.prototype.removeAllListeners = Emitter.prototype.removeEventListener = function (event, fn) {
    this._callbacks = this._callbacks || {};
    // all
    if (0 == arguments.length) {
        this._callbacks = {};
        return this;
    }
    // specific event
    var callbacks = this._callbacks['$' + event];
    if (!callbacks)
        return this;
    // remove all handlers
    if (1 == arguments.length) {
        delete this._callbacks['$' + event];
        return this;
    }
    // remove specific handler
    var cb;
    for (var i = 0; i < callbacks.length; i++) {
        cb = callbacks[i];
        if (cb === fn || cb.fn === fn) {
            callbacks.splice(i, 1);
            break;
        }
    }
    return this;
};
/**
 * Emit `event` with the given args.
 *
 * @param {String} event
 * @param {Mixed} ...
 * @return {Emitter}
 */
Emitter.prototype.emit = function (event) {
    this._callbacks = this._callbacks || {};
    var args = [].slice.call(arguments, 1), callbacks = this._callbacks['$' + event];
    if (callbacks) {
        callbacks = callbacks.slice(0);
        for (var i = 0, len = callbacks.length; i < len; ++i) {
            callbacks[i].apply(this, args);
        }
    }
    return this;
};
/**
 * Return array of callbacks for `event`.
 *
 * @param {String} event
 * @return {Array}
 * @api public
 */
Emitter.prototype.listeners = function (event) {
    this._callbacks = this._callbacks || {};
    return this._callbacks['$' + event] || [];
};
/**
 * Check if this emitter has `event` handlers.
 *
 * @param {String} event
 * @return {Boolean}
 * @api public
 */
Emitter.prototype.hasListeners = function (event) {
    return !!this.listeners(event).length;
};