Current File : //lib/node_modules/pm2/node_modules/vm2/lib/events.js
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
// Modified by the vm2 team to make this a standalone module to be loaded into the sandbox.
'use strict';
const host = fromhost;
const {
Boolean,
Error,
String,
Symbol
} = globalThis;
const ReflectApply = Reflect.apply;
const ReflectOwnKeys = Reflect.ownKeys;
const ErrorCaptureStackTrace = Error.captureStackTrace;
const NumberIsNaN = Number.isNaN;
const ObjectCreate = Object.create;
const ObjectDefineProperty = Object.defineProperty;
const ObjectDefineProperties = Object.defineProperties;
const ObjectGetPrototypeOf = Object.getPrototypeOf;
const SymbolFor = Symbol.for;
function uncurryThis(func) {
return (thiz, ...args) => ReflectApply(func, thiz, args);
}
const ArrayPrototypeIndexOf = uncurryThis(Array.prototype.indexOf);
const ArrayPrototypeJoin = uncurryThis(Array.prototype.join);
const ArrayPrototypeSlice = uncurryThis(Array.prototype.slice);
const ArrayPrototypeSplice = uncurryThis(Array.prototype.splice);
const ArrayPrototypeUnshift = uncurryThis(Array.prototype.unshift);
const kRejection = SymbolFor('nodejs.rejection');
function inspect(obj) {
return typeof obj === 'symbol' ? obj.toString() : `${obj}`;
}
function spliceOne(list, index) {
for (; index + 1 < list.length; index++)
list[index] = list[index + 1];
list.pop();
}
function assert(what, message) {
if (!what) throw new Error(message);
}
function E(key, msg, Base) {
return function NodeError(...args) {
const error = new Base();
const message = ReflectApply(msg, error, args);
ObjectDefineProperties(error, {
message: {
value: message,
enumerable: false,
writable: true,
configurable: true,
},
toString: {
value() {
return `${this.name} [${key}]: ${this.message}`;
},
enumerable: false,
writable: true,
configurable: true,
},
});
error.code = key;
return error;
};
}
const ERR_INVALID_ARG_TYPE = E('ERR_INVALID_ARG_TYPE',
(name, expected, actual) => {
assert(typeof name === 'string', "'name' must be a string");
if (!ArrayIsArray(expected)) {
expected = [expected];
}
let msg = 'The ';
if (StringPrototypeEndsWith(name, ' argument')) {
// For cases like 'first argument'
msg += `${name} `;
} else {
const type = StringPrototypeIncludes(name, '.') ? 'property' : 'argument';
msg += `"${name}" ${type} `;
}
msg += 'must be ';
const types = [];
const instances = [];
const other = [];
for (const value of expected) {
assert(typeof value === 'string',
'All expected entries have to be of type string');
if (ArrayPrototypeIncludes(kTypes, value)) {
ArrayPrototypePush(types, StringPrototypeToLowerCase(value));
} else if (RegExpPrototypeTest(classRegExp, value)) {
ArrayPrototypePush(instances, value);
} else {
assert(value !== 'object',
'The value "object" should be written as "Object"');
ArrayPrototypePush(other, value);
}
}
// Special handle `object` in case other instances are allowed to outline
// the differences between each other.
if (instances.length > 0) {
const pos = ArrayPrototypeIndexOf(types, 'object');
if (pos !== -1) {
ArrayPrototypeSplice(types, pos, 1);
ArrayPrototypePush(instances, 'Object');
}
}
if (types.length > 0) {
if (types.length > 2) {
const last = ArrayPrototypePop(types);
msg += `one of type ${ArrayPrototypeJoin(types, ', ')}, or ${last}`;
} else if (types.length === 2) {
msg += `one of type ${types[0]} or ${types[1]}`;
} else {
msg += `of type ${types[0]}`;
}
if (instances.length > 0 || other.length > 0)
msg += ' or ';
}
if (instances.length > 0) {
if (instances.length > 2) {
const last = ArrayPrototypePop(instances);
msg +=
`an instance of ${ArrayPrototypeJoin(instances, ', ')}, or ${last}`;
} else {
msg += `an instance of ${instances[0]}`;
if (instances.length === 2) {
msg += ` or ${instances[1]}`;
}
}
if (other.length > 0)
msg += ' or ';
}
if (other.length > 0) {
if (other.length > 2) {
const last = ArrayPrototypePop(other);
msg += `one of ${ArrayPrototypeJoin(other, ', ')}, or ${last}`;
} else if (other.length === 2) {
msg += `one of ${other[0]} or ${other[1]}`;
} else {
if (StringPrototypeToLowerCase(other[0]) !== other[0])
msg += 'an ';
msg += `${other[0]}`;
}
}
if (actual == null) {
msg += `. Received ${actual}`;
} else if (typeof actual === 'function' && actual.name) {
msg += `. Received function ${actual.name}`;
} else if (typeof actual === 'object') {
if (actual.constructor && actual.constructor.name) {
msg += `. Received an instance of ${actual.constructor.name}`;
} else {
const inspected = inspect(actual, { depth: -1 });
msg += `. Received ${inspected}`;
}
} else {
let inspected = inspect(actual, { colors: false });
if (inspected.length > 25)
inspected = `${StringPrototypeSlice(inspected, 0, 25)}...`;
msg += `. Received type ${typeof actual} (${inspected})`;
}
return msg;
}, TypeError);
const ERR_INVALID_THIS = E('ERR_INVALID_THIS', s => `Value of "this" must be of type ${s}`, TypeError);
const ERR_OUT_OF_RANGE = E('ERR_OUT_OF_RANGE',
(str, range, input, replaceDefaultBoolean = false) => {
assert(range, 'Missing "range" argument');
let msg = replaceDefaultBoolean ? str :
`The value of "${str}" is out of range.`;
const received = inspect(input);
msg += ` It must be ${range}. Received ${received}`;
return msg;
}, RangeError);
const ERR_UNHANDLED_ERROR = E('ERR_UNHANDLED_ERROR',
err => {
const msg = 'Unhandled error.';
if (err === undefined) return msg;
return `${msg} (${err})`;
}, Error);
function validateBoolean(value, name) {
if (typeof value !== 'boolean')
throw new ERR_INVALID_ARG_TYPE(name, 'boolean', value);
}
function validateFunction(value, name) {
if (typeof value !== 'function')
throw new ERR_INVALID_ARG_TYPE(name, 'Function', value);
}
function validateString(value, name) {
if (typeof value !== 'string')
throw new ERR_INVALID_ARG_TYPE(name, 'string', value);
}
function nc(cond, e) {
return cond === undefined || cond === null ? e : cond;
}
function oc(base, key) {
return base === undefined || base === null ? undefined : base[key];
}
const kCapture = Symbol('kCapture');
const kErrorMonitor = host.kErrorMonitor || Symbol('events.errorMonitor');
const kMaxEventTargetListeners = Symbol('events.maxEventTargetListeners');
const kMaxEventTargetListenersWarned =
Symbol('events.maxEventTargetListenersWarned');
const kIsEventTarget = SymbolFor('nodejs.event_target');
function isEventTarget(obj) {
return oc(oc(obj, 'constructor'), kIsEventTarget);
}
/**
* Creates a new `EventEmitter` instance.
* @param {{ captureRejections?: boolean; }} [opts]
* @constructs {EventEmitter}
*/
function EventEmitter(opts) {
EventEmitter.init.call(this, opts);
}
module.exports = EventEmitter;
if (host.once) module.exports.once = host.once;
if (host.on) module.exports.on = host.on;
if (host.getEventListeners) module.exports.getEventListeners = host.getEventListeners;
// Backwards-compat with node 0.10.x
EventEmitter.EventEmitter = EventEmitter;
EventEmitter.usingDomains = false;
EventEmitter.captureRejectionSymbol = kRejection;
ObjectDefineProperty(EventEmitter, 'captureRejections', {
get() {
return EventEmitter.prototype[kCapture];
},
set(value) {
validateBoolean(value, 'EventEmitter.captureRejections');
EventEmitter.prototype[kCapture] = value;
},
enumerable: true
});
if (host.EventEmitterReferencingAsyncResource) {
const kAsyncResource = Symbol('kAsyncResource');
const EventEmitterReferencingAsyncResource = host.EventEmitterReferencingAsyncResource;
class EventEmitterAsyncResource extends EventEmitter {
/**
* @param {{
* name?: string,
* triggerAsyncId?: number,
* requireManualDestroy?: boolean,
* }} [options]
*/
constructor(options = undefined) {
let name;
if (typeof options === 'string') {
name = options;
options = undefined;
} else {
if (new.target === EventEmitterAsyncResource) {
validateString(oc(options, 'name'), 'options.name');
}
name = oc(options, 'name') || new.target.name;
}
super(options);
this[kAsyncResource] =
new EventEmitterReferencingAsyncResource(this, name, options);
}
/**
* @param {symbol,string} event
* @param {...any} args
* @returns {boolean}
*/
emit(event, ...args) {
if (this[kAsyncResource] === undefined)
throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
const { asyncResource } = this;
ArrayPrototypeUnshift(args, super.emit, this, event);
return ReflectApply(asyncResource.runInAsyncScope, asyncResource,
args);
}
/**
* @returns {void}
*/
emitDestroy() {
if (this[kAsyncResource] === undefined)
throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
this.asyncResource.emitDestroy();
}
/**
* @type {number}
*/
get asyncId() {
if (this[kAsyncResource] === undefined)
throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
return this.asyncResource.asyncId();
}
/**
* @type {number}
*/
get triggerAsyncId() {
if (this[kAsyncResource] === undefined)
throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
return this.asyncResource.triggerAsyncId();
}
/**
* @type {EventEmitterReferencingAsyncResource}
*/
get asyncResource() {
if (this[kAsyncResource] === undefined)
throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
return this[kAsyncResource];
}
}
EventEmitter.EventEmitterAsyncResource = EventEmitterAsyncResource;
}
EventEmitter.errorMonitor = kErrorMonitor;
// The default for captureRejections is false
ObjectDefineProperty(EventEmitter.prototype, kCapture, {
value: false,
writable: true,
enumerable: false
});
EventEmitter.prototype._events = undefined;
EventEmitter.prototype._eventsCount = 0;
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.
let defaultMaxListeners = 10;
function checkListener(listener) {
validateFunction(listener, 'listener');
}
ObjectDefineProperty(EventEmitter, 'defaultMaxListeners', {
enumerable: true,
get: function() {
return defaultMaxListeners;
},
set: function(arg) {
if (typeof arg !== 'number' || arg < 0 || NumberIsNaN(arg)) {
throw new ERR_OUT_OF_RANGE('defaultMaxListeners',
'a non-negative number',
arg);
}
defaultMaxListeners = arg;
}
});
ObjectDefineProperties(EventEmitter, {
kMaxEventTargetListeners: {
value: kMaxEventTargetListeners,
enumerable: false,
configurable: false,
writable: false,
},
kMaxEventTargetListenersWarned: {
value: kMaxEventTargetListenersWarned,
enumerable: false,
configurable: false,
writable: false,
}
});
/**
* Sets the max listeners.
* @param {number} n
* @param {EventTarget[] | EventEmitter[]} [eventTargets]
* @returns {void}
*/
EventEmitter.setMaxListeners =
function(n = defaultMaxListeners, ...eventTargets) {
if (typeof n !== 'number' || n < 0 || NumberIsNaN(n))
throw new ERR_OUT_OF_RANGE('n', 'a non-negative number', n);
if (eventTargets.length === 0) {
defaultMaxListeners = n;
} else {
for (let i = 0; i < eventTargets.length; i++) {
const target = eventTargets[i];
if (isEventTarget(target)) {
target[kMaxEventTargetListeners] = n;
target[kMaxEventTargetListenersWarned] = false;
} else if (typeof target.setMaxListeners === 'function') {
target.setMaxListeners(n);
} else {
throw new ERR_INVALID_ARG_TYPE(
'eventTargets',
['EventEmitter', 'EventTarget'],
target);
}
}
}
};
// If you're updating this function definition, please also update any
// re-definitions, such as the one in the Domain module (lib/domain.js).
EventEmitter.init = function(opts) {
if (this._events === undefined ||
this._events === ObjectGetPrototypeOf(this)._events) {
this._events = ObjectCreate(null);
this._eventsCount = 0;
}
this._maxListeners = this._maxListeners || undefined;
if (oc(opts, 'captureRejections')) {
validateBoolean(opts.captureRejections, 'options.captureRejections');
this[kCapture] = Boolean(opts.captureRejections);
} else {
// Assigning the kCapture property directly saves an expensive
// prototype lookup in a very sensitive hot path.
this[kCapture] = EventEmitter.prototype[kCapture];
}
};
function addCatch(that, promise, type, args) {
if (!that[kCapture]) {
return;
}
// Handle Promises/A+ spec, then could be a getter
// that throws on second use.
try {
const then = promise.then;
if (typeof then === 'function') {
then.call(promise, undefined, function(err) {
// The callback is called with nextTick to avoid a follow-up
// rejection from this promise.
process.nextTick(emitUnhandledRejectionOrErr, that, err, type, args);
});
}
} catch (err) {
that.emit('error', err);
}
}
function emitUnhandledRejectionOrErr(ee, err, type, args) {
if (typeof ee[kRejection] === 'function') {
ee[kRejection](err, type, ...args);
} else {
// We have to disable the capture rejections mechanism, otherwise
// we might end up in an infinite loop.
const prev = ee[kCapture];
// If the error handler throws, it is not catchable and it
// will end up in 'uncaughtException'. We restore the previous
// value of kCapture in case the uncaughtException is present
// and the exception is handled.
try {
ee[kCapture] = false;
ee.emit('error', err);
} finally {
ee[kCapture] = prev;
}
}
}
/**
* Increases the max listeners of the event emitter.
* @param {number} n
* @returns {EventEmitter}
*/
EventEmitter.prototype.setMaxListeners = function setMaxListeners(n) {
if (typeof n !== 'number' || n < 0 || NumberIsNaN(n)) {
throw new ERR_OUT_OF_RANGE('n', 'a non-negative number', n);
}
this._maxListeners = n;
return this;
};
function _getMaxListeners(that) {
if (that._maxListeners === undefined)
return EventEmitter.defaultMaxListeners;
return that._maxListeners;
}
/**
* Returns the current max listener value for the event emitter.
* @returns {number}
*/
EventEmitter.prototype.getMaxListeners = function getMaxListeners() {
return _getMaxListeners(this);
};
/**
* Synchronously calls each of the listeners registered
* for the event.
* @param {string | symbol} type
* @param {...any} [args]
* @returns {boolean}
*/
EventEmitter.prototype.emit = function emit(type, ...args) {
let doError = (type === 'error');
const events = this._events;
if (events !== undefined) {
if (doError && events[kErrorMonitor] !== undefined)
this.emit(kErrorMonitor, ...args);
doError = (doError && events.error === undefined);
} else if (!doError)
return false;
// If there is no 'error' event listener then throw.
if (doError) {
let er;
if (args.length > 0)
er = args[0];
if (er instanceof Error) {
try {
const capture = {};
ErrorCaptureStackTrace(capture, EventEmitter.prototype.emit);
} catch (e) {}
// Note: The comments on the `throw` lines are intentional, they show
// up in Node's output if this results in an unhandled exception.
throw er; // Unhandled 'error' event
}
let stringifiedEr;
try {
stringifiedEr = inspect(er);
} catch (e) {
stringifiedEr = er;
}
// At least give some kind of context to the user
const err = new ERR_UNHANDLED_ERROR(stringifiedEr);
err.context = er;
throw err; // Unhandled 'error' event
}
const handler = events[type];
if (handler === undefined)
return false;
if (typeof handler === 'function') {
const result = handler.apply(this, args);
// We check if result is undefined first because that
// is the most common case so we do not pay any perf
// penalty
if (result !== undefined && result !== null) {
addCatch(this, result, type, args);
}
} else {
const len = handler.length;
const listeners = arrayClone(handler);
for (let i = 0; i < len; ++i) {
const result = listeners[i].apply(this, args);
// We check if result is undefined first because that
// is the most common case so we do not pay any perf
// penalty.
// This code is duplicated because extracting it away
// would make it non-inlineable.
if (result !== undefined && result !== null) {
addCatch(this, result, type, args);
}
}
}
return true;
};
function _addListener(target, type, listener, prepend) {
let m;
let events;
let existing;
checkListener(listener);
events = target._events;
if (events === undefined) {
events = target._events = ObjectCreate(null);
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 !== undefined) {
target.emit('newListener', type,
nc(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 === undefined) {
// Optimize the case of one listener. Don't need the extra array object.
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];
// If we've already got an array, just append.
} else if (prepend) {
existing.unshift(listener);
} else {
existing.push(listener);
}
// Check for listener leak
m = _getMaxListeners(target);
if (m > 0 && existing.length > m && !existing.warned) {
existing.warned = true;
// No error code for this since it is a Warning
// eslint-disable-next-line no-restricted-syntax
const w = new Error('Possible EventEmitter memory leak detected. ' +
`${existing.length} ${String(type)} listeners ` +
`added to ${inspect(target, { depth: -1 })}. Use ` +
'emitter.setMaxListeners() to increase limit');
w.name = 'MaxListenersExceededWarning';
w.emitter = target;
w.type = type;
w.count = existing.length;
process.emitWarning(w);
}
}
return target;
}
/**
* Adds a listener to the event emitter.
* @param {string | symbol} type
* @param {Function} listener
* @returns {EventEmitter}
*/
EventEmitter.prototype.addListener = function addListener(type, listener) {
return _addListener(this, type, listener, false);
};
EventEmitter.prototype.on = EventEmitter.prototype.addListener;
/**
* Adds the `listener` function to the beginning of
* the listeners array.
* @param {string | symbol} type
* @param {Function} listener
* @returns {EventEmitter}
*/
EventEmitter.prototype.prependListener =
function prependListener(type, listener) {
return _addListener(this, type, listener, true);
};
function onceWrapper() {
if (!this.fired) {
this.target.removeListener(this.type, this.wrapFn);
this.fired = true;
if (arguments.length === 0)
return this.listener.call(this.target);
return this.listener.apply(this.target, arguments);
}
}
function _onceWrap(target, type, listener) {
const state = { fired: false, wrapFn: undefined, target, type, listener };
const wrapped = onceWrapper.bind(state);
wrapped.listener = listener;
state.wrapFn = wrapped;
return wrapped;
}
/**
* Adds a one-time `listener` function to the event emitter.
* @param {string | symbol} type
* @param {Function} listener
* @returns {EventEmitter}
*/
EventEmitter.prototype.once = function once(type, listener) {
checkListener(listener);
this.on(type, _onceWrap(this, type, listener));
return this;
};
/**
* Adds a one-time `listener` function to the beginning of
* the listeners array.
* @param {string | symbol} type
* @param {Function} listener
* @returns {EventEmitter}
*/
EventEmitter.prototype.prependOnceListener =
function prependOnceListener(type, listener) {
checkListener(listener);
this.prependListener(type, _onceWrap(this, type, listener));
return this;
};
/**
* Removes the specified `listener` from the listeners array.
* @param {string | symbol} type
* @param {Function} listener
* @returns {EventEmitter}
*/
EventEmitter.prototype.removeListener =
function removeListener(type, listener) {
checkListener(listener);
const events = this._events;
if (events === undefined)
return this;
const list = events[type];
if (list === undefined)
return this;
if (list === listener || list.listener === listener) {
if (--this._eventsCount === 0)
this._events = ObjectCreate(null);
else {
delete events[type];
if (events.removeListener)
this.emit('removeListener', type, list.listener || listener);
}
} else if (typeof list !== 'function') {
let position = -1;
for (let i = list.length - 1; i >= 0; i--) {
if (list[i] === listener || list[i].listener === listener) {
position = i;
break;
}
}
if (position < 0)
return this;
if (position === 0)
list.shift();
else {
spliceOne(list, position);
}
if (list.length === 1)
events[type] = list[0];
if (events.removeListener !== undefined)
this.emit('removeListener', type, listener);
}
return this;
};
EventEmitter.prototype.off = EventEmitter.prototype.removeListener;
/**
* Removes all listeners from the event emitter. (Only
* removes listeners for a specific event name if specified
* as `type`).
* @param {string | symbol} [type]
* @returns {EventEmitter}
*/
EventEmitter.prototype.removeAllListeners =
function removeAllListeners(type) {
const events = this._events;
if (events === undefined)
return this;
// Not listening for removeListener, no need to emit
if (events.removeListener === undefined) {
if (arguments.length === 0) {
this._events = ObjectCreate(null);
this._eventsCount = 0;
} else if (events[type] !== undefined) {
if (--this._eventsCount === 0)
this._events = ObjectCreate(null);
else
delete events[type];
}
return this;
}
// Emit removeListener for all listeners on all events
if (arguments.length === 0) {
for (const key of ReflectOwnKeys(events)) {
if (key === 'removeListener') continue;
this.removeAllListeners(key);
}
this.removeAllListeners('removeListener');
this._events = ObjectCreate(null);
this._eventsCount = 0;
return this;
}
const listeners = events[type];
if (typeof listeners === 'function') {
this.removeListener(type, listeners);
} else if (listeners !== undefined) {
// LIFO order
for (let i = listeners.length - 1; i >= 0; i--) {
this.removeListener(type, listeners[i]);
}
}
return this;
};
function _listeners(target, type, unwrap) {
const events = target._events;
if (events === undefined)
return [];
const evlistener = events[type];
if (evlistener === undefined)
return [];
if (typeof evlistener === 'function')
return unwrap ? [evlistener.listener || evlistener] : [evlistener];
return unwrap ?
unwrapListeners(evlistener) : arrayClone(evlistener);
}
/**
* Returns a copy of the array of listeners for the event name
* specified as `type`.
* @param {string | symbol} type
* @returns {Function[]}
*/
EventEmitter.prototype.listeners = function listeners(type) {
return _listeners(this, type, true);
};
/**
* Returns a copy of the array of listeners and wrappers for
* the event name specified as `type`.
* @param {string | symbol} type
* @returns {Function[]}
*/
EventEmitter.prototype.rawListeners = function rawListeners(type) {
return _listeners(this, type, false);
};
/**
* Returns the number of listeners listening to the event name
* specified as `type`.
* @deprecated since v3.2.0
* @param {EventEmitter} emitter
* @param {string | symbol} type
* @returns {number}
*/
EventEmitter.listenerCount = function(emitter, type) {
if (typeof emitter.listenerCount === 'function') {
return emitter.listenerCount(type);
}
return emitter.listenerCount(type);
};
EventEmitter.prototype.listenerCount = listenerCount;
/**
* Returns the number of listeners listening to event name
* specified as `type`.
* @param {string | symbol} type
* @returns {number}
*/
function listenerCount(type) {
const events = this._events;
if (events !== undefined) {
const evlistener = events[type];
if (typeof evlistener === 'function') {
return 1;
} else if (evlistener !== undefined) {
return evlistener.length;
}
}
return 0;
}
/**
* Returns an array listing the events for which
* the emitter has registered listeners.
* @returns {any[]}
*/
EventEmitter.prototype.eventNames = function eventNames() {
return this._eventsCount > 0 ? ReflectOwnKeys(this._events) : [];
};
function arrayClone(arr) {
// At least since V8 8.3, this implementation is faster than the previous
// which always used a simple for-loop
switch (arr.length) {
case 2: return [arr[0], arr[1]];
case 3: return [arr[0], arr[1], arr[2]];
case 4: return [arr[0], arr[1], arr[2], arr[3]];
case 5: return [arr[0], arr[1], arr[2], arr[3], arr[4]];
case 6: return [arr[0], arr[1], arr[2], arr[3], arr[4], arr[5]];
}
return ArrayPrototypeSlice(arr);
}
function unwrapListeners(arr) {
const ret = arrayClone(arr);
for (let i = 0; i < ret.length; ++i) {
const orig = ret[i].listener;
if (typeof orig === 'function')
ret[i] = orig;
}
return ret;
}
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