'use strict';
var domain;
// This constructor is used to store event handlers. Instantiating this is
// faster than explicitly calling `Object.create(null)` to get a "clean" empty
// object (tested with v8 v4.9).
function EventHandlers() {}
EventHandlers.prototype = Object.create(null);
function EventEmitter() {
EventEmitter.init.call(this);
}
module.exports = EventEmitter;
// Backwards-compat with node 0.10.x
EventEmitter.EventEmitter = EventEmitter;
EventEmitter.usingDomains = false;
EventEmitter.prototype.domain = undefined;
EventEmitter.prototype._events = undefined;
EventEmitter.prototype._maxListeners = undefined;
// By default EventEmitters will print a warning if more than 10 listeners are
// added to it. This is a useful default which helps finding memory leaks.
var defaultMaxListeners = 10;
Object.defineProperty(EventEmitter, 'defaultMaxListeners', {
enumerable: true,
get: function() {
return defaultMaxListeners;
},
set: function(arg) {
// force global console to be compiled.
// see https://github.com/nodejs/node/issues/4467
console;
defaultMaxListeners = arg;
}
});
EventEmitter.init = function() {
this.domain = null;
if (EventEmitter.usingDomains) {
// if there is an active domain, then attach to it.
domain = domain || require('domain');
if (domain.active && !(this instanceof domain.Domain)) {
this.domain = domain.active;
}
}
if (!this._events || this._events === Object.getPrototypeOf(this)._events) {
this._events = new EventHandlers();
this._eventsCount = 0;
}
this._maxListeners = this._maxListeners || undefined;
};
// Obviously not all Emitters should be limited to 10. This function allows
// that to be increased. Set to zero for unlimited.
EventEmitter.prototype.setMaxListeners = function setMaxListeners(n) {
if (typeof n !== 'number' || n < 0 || isNaN(n))
throw new TypeError('"n" argument must be a positive number');
this._maxListeners = n;
return this;
};
function $getMaxListeners(that) {
if (that._maxListeners === undefined)
return EventEmitter.defaultMaxListeners;
return that._maxListeners;
}
EventEmitter.prototype.getMaxListeners = function getMaxListeners() {
return $getMaxListeners(this);
};
// These standalone emit* functions are used to optimize calling of event
// handlers for fast cases because emit() itself often has a variable number of
// arguments and can be deoptimized because of that. These functions always have
// the same number of arguments and thus do not get deoptimized, so the code
// inside them can execute faster.
function emitNone(handler, isFn, self) {
if (isFn)
handler.call(self);
else {
var len = handler.length;
var listeners = arrayClone(handler, len);
for (var i = 0; i < len; ++i)
listeners[i].call(self);
}
}
function emitOne(handler, isFn, self, arg1) {
if (isFn)
handler.call(self, arg1);
else {
var len = handler.length;
var listeners = arrayClone(handler, len);
for (var i = 0; i < len; ++i)
listeners[i].call(self, arg1);
}
}
function emitTwo(handler, isFn, self, arg1, arg2) {
if (isFn)
handler.call(self, arg1, arg2);
else {
var len = handler.length;
var listeners = arrayClone(handler, len);
for (var i = 0; i < len; ++i)
listeners[i].call(self, arg1, arg2);
}
}
function emitThree(handler, isFn, self, arg1, arg2, arg3) {
if (isFn)
handler.call(self, arg1, arg2, arg3);
else {
var len = handler.length;
var listeners = arrayClone(handler, len);
for (var i = 0; i < len; ++i)
listeners[i].call(self, arg1, arg2, arg3);
}
}
function emitMany(handler, isFn, self, args) {
if (isFn)
handler.apply(self, args);
else {
var len = handler.length;
var listeners = arrayClone(handler, len);
for (var i = 0; i < len; ++i)
listeners[i].apply(self, args);
}
}
EventEmitter.prototype.emit = function emit(type) {
var er, handler, len, args, i, events, domain;
var needDomainExit = false;
var doError = (type === 'error');
events = this._events;
if (events)
doError = (doError && events.error == null);
else if (!doError)
return false;
domain = this.domain;
// If there is no 'error' event listener then throw.
if (doError) {
er = arguments[1];
if (domain) {
if (!er)
er = new Error('Uncaught, unspecified "error" event');
er.domainEmitter = this;
er.domain = domain;
er.domainThrown = false;
domain.emit('error', er);
} else if (er instanceof Error) {
throw er; // Unhandled 'error' event
} else {
// At least give some kind of context to the user
var err = new Error('Uncaught, unspecified "error" event. (' + er + ')');
err.context = er;
throw err;
}
return false;
}
handler = events[type];
if (!handler)
return false;
if (domain && this !== process) {
domain.enter();
needDomainExit = true;
}
var isFn = typeof handler === 'function';
len = arguments.length;
switch (len) {
// fast cases
case 1:
emitNone(handler, isFn, this);
break;
case 2:
emitOne(handler, isFn, this, arguments[1]);
break;
case 3:
emitTwo(handler, isFn, this, arguments[1], arguments[2]);
break;
case 4:
emitThree(handler, isFn, this, arguments[1], arguments[2], arguments[3]);
break;
// slower
default:
args = new Array(len - 1);
for (i = 1; i < len; i++)
args[i - 1] = arguments[i];
emitMany(handler, isFn, this, args);
}
if (needDomainExit)
domain.exit();
return true;
};
function _addListener(target, type, listener, prepend) {
var m;
var events;
var existing;
if (typeof listener !== 'function')
throw new TypeError('"listener" argument must be a function');
events = target._events;
if (!events) {
events = target._events = new EventHandlers();
target._eventsCount = 0;
} else {
// To avoid recursion in the case that type === "newListener"! Before
// adding it to the listeners, first emit "newListener".
if (events.newListener) {
target.emit('newListener', type,
listener.listener ? listener.listener : listener);
// Re-assign `events` because a newListener handler could have caused the
// this._events to be assigned to a new object
events = target._events;
}
existing = events[type];
}
if (!existing) {
// Optimize the case of one listener. Don't need the extra array object.
existing = events[type] = listener;
++target._eventsCount;
} else {
if (typeof existing === 'function') {
// Adding the second element, need to change to array.
existing = events[type] = prepend ? [listener, existing] : [existing, listener];
} else {
// If we've already got an array, just append.
if (prepend) {
existing.unshift(listener);
} else {
existing.push(listener);
}
}
// Check for listener leak
if (!existing.warned) {
m = $getMaxListeners(target);
if (m && m > 0 && existing.length > m) {
existing.warned = true;
const w = new Error('Possible EventEmitter memory leak detected. ' +
`${existing.length} ${type} listeners added. ` +
'Use emitter.setMaxListeners() to increase limit');
w.name = 'Warning';
w.emitter = target;
w.type = type;
w.count = existing.length;
process.emitWarning(w);
}
}
}
return target;
}
EventEmitter.prototype.addListener = function addListener(type, listener) {
return _addListener(this, type, listener, false);
};
EventEmitter.prototype.on = EventEmitter.prototype.addListener;
EventEmitter.prototype.prependListener =
function prependListener(type, listener) {
return _addListener(this, type, listener, true);
};
function _onceWrap(target, type, listener) {
var fired = false;
function g() {
target.removeListener(type, g);
if (!fired) {
fired = true;
listener.apply(target, arguments);
}
}
g.listener = listener;
return g;
}
EventEmitter.prototype.once = function once(type, listener) {
if (typeof listener !== 'function')
throw new TypeError('"listener" argument must be a function');
this.on(type, _onceWrap(this, type, listener));
return this;
};
EventEmitter.prototype.prependOnceListener =
function prependOnceListener(type, listener) {
if (typeof listener !== 'function')
throw new TypeError('"listener" argument must be a function');
this.prependListener(type, _onceWrap(this, type, listener));
return this;
};
// emits a 'removeListener' event iff the listener was removed
EventEmitter.prototype.removeListener =
function removeListener(type, listener) {
var list, events, position, i, originalListener;
if (typeof listener !== 'function')
throw new TypeError('"listener" argument must be a function');
events = this._events;
if (!events)
return this;
list = events[type];
if (!list)
return this;
if (list === listener || list.listener === listener) {
if (--this._eventsCount === 0)
this._events = new EventHandlers();
else {
delete events[type];
if (events.removeListener)
this.emit('removeListener', type, list.listener || listener);
}
} else if (typeof list !== 'function') {
position = -1;
for (i = list.length; i-- > 0;) {
if (list[i] === listener || list[i].listener === listener) {
originalListener = list[i].listener;
position = i;
break;
}
}
if (position < 0)
return this;
if (list.length === 1) {
list[0] = undefined;
if (--this._eventsCount === 0) {
this._events = new EventHandlers();
return this;
} else {
delete events[type];
}
} else {
spliceOne(list, position);
}
if (events.removeListener)
this.emit('removeListener', type, originalListener || listener);
}
return this;
};
EventEmitter.prototype.removeAllListeners =
function removeAllListeners(type) {
var listeners, events;
events = this._events;
if (!events)
return this;
// not listening for removeListener, no need to emit
if (!events.removeListener) {
if (arguments.length === 0) {
this._events = new EventHandlers();
this._eventsCount = 0;
} else if (events[type]) {
if (--this._eventsCount === 0)
this._events = new EventHandlers();
else
delete events[type];
}
return this;
}
// emit removeListener for all listeners on all events
if (arguments.length === 0) {
var keys = Object.keys(events);
for (var i = 0, key; i < keys.length; ++i) {
key = keys[i];
if (key === 'removeListener') continue;
this.removeAllListeners(key);
}
this.removeAllListeners('removeListener');
this._events = new EventHandlers();
this._eventsCount = 0;
return this;
}
listeners = events[type];
if (typeof listeners === 'function') {
this.removeListener(type, listeners);
} else if (listeners) {
// LIFO order
do {
this.removeListener(type, listeners[listeners.length - 1]);
} while (listeners[0]);
}
return this;
};
EventEmitter.prototype.listeners = function listeners(type) {
var evlistener;
var ret;
var events = this._events;
if (!events)
ret = [];
else {
evlistener = events[type];
if (!evlistener)
ret = [];
else if (typeof evlistener === 'function')
ret = [evlistener];
else
ret = arrayClone(evlistener, evlistener.length);
}
return ret;
};
EventEmitter.listenerCount = function(emitter, type) {
if (typeof emitter.listenerCount === 'function') {
return emitter.listenerCount(type);
} else {
return listenerCount.call(emitter, type);
}
};
EventEmitter.prototype.listenerCount = listenerCount;
function listenerCount(type) {
const events = this._events;
if (events) {
const evlistener = events[type];
if (typeof evlistener === 'function') {
return 1;
} else if (evlistener) {
return evlistener.length;
}
}
return 0;
}
EventEmitter.prototype.eventNames = function eventNames() {
return this._eventsCount > 0 ? Reflect.ownKeys(this._events) : [];
};
// About 1.5x faster than the two-arg version of Array#splice().
function spliceOne(list, index) {
for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1)
list[i] = list[k];
list.pop();
}
function arrayClone(arr, i) {
var copy = new Array(i);
while (i--)
copy[i] = arr[i];
return copy;
}
