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+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+// 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.
+
+"use strict";
+
+const kRejection = Symbol.for("nodejs.rejection");
+
+import { inspect } from "internal:deno_node/polyfills/internal/util/inspect.mjs";
+import {
+ AbortError,
+ // kEnhanceStackBeforeInspector,
+ ERR_INVALID_ARG_TYPE,
+ ERR_OUT_OF_RANGE,
+ ERR_UNHANDLED_ERROR,
+} from "internal:deno_node/polyfills/internal/errors.ts";
+
+import {
+ validateAbortSignal,
+ validateBoolean,
+ validateFunction,
+} from "internal:deno_node/polyfills/internal/validators.mjs";
+import { spliceOne } from "internal:deno_node/polyfills/_utils.ts";
+
+const kCapture = Symbol("kCapture");
+const kErrorMonitor = Symbol("events.errorMonitor");
+const kMaxEventTargetListeners = Symbol("events.maxEventTargetListeners");
+const kMaxEventTargetListenersWarned = Symbol(
+ "events.maxEventTargetListenersWarned",
+);
+
+/**
+ * Creates a new `EventEmitter` instance.
+ * @param {{ captureRejections?: boolean; }} [opts]
+ * @returns {EventEmitter}
+ */
+export function EventEmitter(opts) {
+ EventEmitter.init.call(this, opts);
+}
+export default EventEmitter;
+EventEmitter.on = on;
+EventEmitter.once = once;
+EventEmitter.getEventListeners = getEventListeners;
+EventEmitter.setMaxListeners = setMaxListeners;
+EventEmitter.listenerCount = listenerCount;
+// Backwards-compat with node 0.10.x
+EventEmitter.EventEmitter = EventEmitter;
+EventEmitter.usingDomains = false;
+
+EventEmitter.captureRejectionSymbol = kRejection;
+export const captureRejectionSymbol = EventEmitter.captureRejectionSymbol;
+export const errorMonitor = EventEmitter.errorMonitor;
+
+Object.defineProperty(EventEmitter, "captureRejections", {
+ get() {
+ return EventEmitter.prototype[kCapture];
+ },
+ set(value) {
+ validateBoolean(value, "EventEmitter.captureRejections");
+
+ EventEmitter.prototype[kCapture] = value;
+ },
+ enumerable: true,
+});
+
+EventEmitter.errorMonitor = kErrorMonitor;
+
+// The default for captureRejections is false
+Object.defineProperty(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.
+export let defaultMaxListeners = 10;
+
+function checkListener(listener) {
+ validateFunction(listener, "listener");
+}
+
+Object.defineProperty(EventEmitter, "defaultMaxListeners", {
+ enumerable: true,
+ get: function () {
+ return defaultMaxListeners;
+ },
+ set: function (arg) {
+ if (typeof arg !== "number" || arg < 0 || Number.isNaN(arg)) {
+ throw new ERR_OUT_OF_RANGE(
+ "defaultMaxListeners",
+ "a non-negative number",
+ arg,
+ );
+ }
+ defaultMaxListeners = arg;
+ },
+});
+
+Object.defineProperties(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}
+ */
+export function setMaxListeners(
+ n = defaultMaxListeners,
+ ...eventTargets
+) {
+ if (typeof n !== "number" || n < 0 || Number.isNaN(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 (target instanceof EventTarget) {
+ 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,
+ );
+ }
+ }
+ }
+}
+
+EventEmitter.init = function (opts) {
+ if (
+ this._events === undefined ||
+ this._events === Object.getPrototypeOf(this)._events
+ ) {
+ this._events = Object.create(null);
+ this._eventsCount = 0;
+ }
+
+ this._maxListeners = this._maxListeners || undefined;
+
+ if (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 catcheable 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 || Number.isNaN(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);
+};
+
+// Returns the length and line number of the first sequence of `a` that fully
+// appears in `b` with a length of at least 4.
+function identicalSequenceRange(a, b) {
+ for (let i = 0; i < a.length - 3; i++) {
+ // Find the first entry of b that matches the current entry of a.
+ const pos = b.indexOf(a[i]);
+ if (pos !== -1) {
+ const rest = b.length - pos;
+ if (rest > 3) {
+ let len = 1;
+ const maxLen = Math.min(a.length - i, rest);
+ // Count the number of consecutive entries.
+ while (maxLen > len && a[i + len] === b[pos + len]) {
+ len++;
+ }
+ if (len > 3) {
+ return [len, i];
+ }
+ }
+ }
+ }
+
+ return [0, 0];
+}
+
+// deno-lint-ignore no-unused-vars
+function enhanceStackTrace(err, own) {
+ let ctorInfo = "";
+ try {
+ const { name } = this.constructor;
+ if (name !== "EventEmitter") {
+ ctorInfo = ` on ${name} instance`;
+ }
+ } catch {
+ // pass
+ }
+ const sep = `\nEmitted 'error' event${ctorInfo} at:\n`;
+
+ const errStack = err.stack.split("\n").slice(1);
+ const ownStack = own.stack.split("\n").slice(1);
+
+ const { 0: len, 1: off } = identicalSequenceRange(ownStack, errStack);
+ if (len > 0) {
+ ownStack.splice(
+ off + 1,
+ len - 2,
+ " [... lines matching original stack trace ...]",
+ );
+ }
+
+ return err.stack + sep + ownStack.join("\n");
+}
+
+/**
+ * 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 = {};
+ Error.captureStackTrace(capture, EventEmitter.prototype.emit);
+ // Object.defineProperty(er, kEnhanceStackBeforeInspector, {
+ // value: enhanceStackTrace.bind(this, er, capture),
+ // configurable: true
+ // });
+ } catch {
+ // pass
+ }
+
+ // 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 {
+ 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 = Object.create(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, 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 = Object.create(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 = Object.create(null);
+ this._eventsCount = 0;
+ } else if (events[type] !== undefined) {
+ if (--this._eventsCount === 0) {
+ this._events = Object.create(null);
+ } else {
+ delete events[type];
+ }
+ }
+ return this;
+ }
+
+ // Emit removeListener for all listeners on all events
+ if (arguments.length === 0) {
+ for (const key of Reflect.ownKeys(events)) {
+ if (key === "removeListener") continue;
+ this.removeAllListeners(key);
+ }
+ this.removeAllListeners("removeListener");
+ this._events = Object.create(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 event name
+ * specified as `type`.
+ * @param {string | symbol} type
+ * @returns {number}
+ */
+const _listenerCount = 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;
+};
+
+EventEmitter.prototype.listenerCount = _listenerCount;
+
+/**
+ * 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}
+ */
+export function listenerCount(emitter, type) {
+ if (typeof emitter.listenerCount === "function") {
+ return emitter.listenerCount(type);
+ }
+ return _listenerCount.call(emitter, type);
+}
+
+/**
+ * Returns an array listing the events for which
+ * the emitter has registered listeners.
+ * @returns {any[]}
+ */
+EventEmitter.prototype.eventNames = function eventNames() {
+ return this._eventsCount > 0 ? Reflect.ownKeys(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 arr.slice();
+}
+
+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;
+}
+
+/**
+ * Returns a copy of the array of listeners for the event name
+ * specified as `type`.
+ * @param {EventEmitter | EventTarget} emitterOrTarget
+ * @param {string | symbol} type
+ * @returns {Function[]}
+ */
+export function getEventListeners(emitterOrTarget, type) {
+ // First check if EventEmitter
+ if (typeof emitterOrTarget.listeners === "function") {
+ return emitterOrTarget.listeners(type);
+ }
+ if (emitterOrTarget instanceof EventTarget) {
+ // TODO: kEvents is not defined
+ const root = emitterOrTarget[kEvents].get(type);
+ const listeners = [];
+ let handler = root?.next;
+ while (handler?.listener !== undefined) {
+ const listener = handler.listener?.deref
+ ? handler.listener.deref()
+ : handler.listener;
+ listeners.push(listener);
+ handler = handler.next;
+ }
+ return listeners;
+ }
+ throw new ERR_INVALID_ARG_TYPE(
+ "emitter",
+ ["EventEmitter", "EventTarget"],
+ emitterOrTarget,
+ );
+}
+
+/**
+ * Creates a `Promise` that is fulfilled when the emitter
+ * emits the given event.
+ * @param {EventEmitter} emitter
+ * @param {string} name
+ * @param {{ signal: AbortSignal; }} [options]
+ * @returns {Promise}
+ */
+// deno-lint-ignore require-await
+export async function once(emitter, name, options = {}) {
+ const signal = options?.signal;
+ validateAbortSignal(signal, "options.signal");
+ if (signal?.aborted) {
+ throw new AbortError();
+ }
+ return new Promise((resolve, reject) => {
+ const errorListener = (err) => {
+ emitter.removeListener(name, resolver);
+ if (signal != null) {
+ eventTargetAgnosticRemoveListener(signal, "abort", abortListener);
+ }
+ reject(err);
+ };
+ const resolver = (...args) => {
+ if (typeof emitter.removeListener === "function") {
+ emitter.removeListener("error", errorListener);
+ }
+ if (signal != null) {
+ eventTargetAgnosticRemoveListener(signal, "abort", abortListener);
+ }
+ resolve(args);
+ };
+ eventTargetAgnosticAddListener(emitter, name, resolver, { once: true });
+ if (name !== "error" && typeof emitter.once === "function") {
+ emitter.once("error", errorListener);
+ }
+ function abortListener() {
+ eventTargetAgnosticRemoveListener(emitter, name, resolver);
+ eventTargetAgnosticRemoveListener(emitter, "error", errorListener);
+ reject(new AbortError());
+ }
+ if (signal != null) {
+ eventTargetAgnosticAddListener(
+ signal,
+ "abort",
+ abortListener,
+ { once: true },
+ );
+ }
+ });
+}
+
+const AsyncIteratorPrototype = Object.getPrototypeOf(
+ Object.getPrototypeOf(async function* () {}).prototype,
+);
+
+function createIterResult(value, done) {
+ return { value, done };
+}
+
+function eventTargetAgnosticRemoveListener(emitter, name, listener, flags) {
+ if (typeof emitter.removeListener === "function") {
+ emitter.removeListener(name, listener);
+ } else if (typeof emitter.removeEventListener === "function") {
+ emitter.removeEventListener(name, listener, flags);
+ } else {
+ throw new ERR_INVALID_ARG_TYPE("emitter", "EventEmitter", emitter);
+ }
+}
+
+function eventTargetAgnosticAddListener(emitter, name, listener, flags) {
+ if (typeof emitter.on === "function") {
+ if (flags?.once) {
+ emitter.once(name, listener);
+ } else {
+ emitter.on(name, listener);
+ }
+ } else if (typeof emitter.addEventListener === "function") {
+ // EventTarget does not have `error` event semantics like Node
+ // EventEmitters, we do not listen to `error` events here.
+ emitter.addEventListener(name, (arg) => {
+ listener(arg);
+ }, flags);
+ } else {
+ throw new ERR_INVALID_ARG_TYPE("emitter", "EventEmitter", emitter);
+ }
+}
+
+/**
+ * Returns an `AsyncIterator` that iterates `event` events.
+ * @param {EventEmitter} emitter
+ * @param {string | symbol} event
+ * @param {{ signal: AbortSignal; }} [options]
+ * @returns {AsyncIterator}
+ */
+export function on(emitter, event, options) {
+ const signal = options?.signal;
+ validateAbortSignal(signal, "options.signal");
+ if (signal?.aborted) {
+ throw new AbortError();
+ }
+
+ const unconsumedEvents = [];
+ const unconsumedPromises = [];
+ let error = null;
+ let finished = false;
+
+ const iterator = Object.setPrototypeOf({
+ next() {
+ // First, we consume all unread events
+ const value = unconsumedEvents.shift();
+ if (value) {
+ return Promise.resolve(createIterResult(value, false));
+ }
+
+ // Then we error, if an error happened
+ // This happens one time if at all, because after 'error'
+ // we stop listening
+ if (error) {
+ const p = Promise.reject(error);
+ // Only the first element errors
+ error = null;
+ return p;
+ }
+
+ // If the iterator is finished, resolve to done
+ if (finished) {
+ return Promise.resolve(createIterResult(undefined, true));
+ }
+
+ // Wait until an event happens
+ return new Promise(function (resolve, reject) {
+ unconsumedPromises.push({ resolve, reject });
+ });
+ },
+
+ return() {
+ eventTargetAgnosticRemoveListener(emitter, event, eventHandler);
+ eventTargetAgnosticRemoveListener(emitter, "error", errorHandler);
+
+ if (signal) {
+ eventTargetAgnosticRemoveListener(
+ signal,
+ "abort",
+ abortListener,
+ { once: true },
+ );
+ }
+
+ finished = true;
+
+ for (const promise of unconsumedPromises) {
+ promise.resolve(createIterResult(undefined, true));
+ }
+
+ return Promise.resolve(createIterResult(undefined, true));
+ },
+
+ throw(err) {
+ if (!err || !(err instanceof Error)) {
+ throw new ERR_INVALID_ARG_TYPE(
+ "EventEmitter.AsyncIterator",
+ "Error",
+ err,
+ );
+ }
+ error = err;
+ eventTargetAgnosticRemoveListener(emitter, event, eventHandler);
+ eventTargetAgnosticRemoveListener(emitter, "error", errorHandler);
+ },
+
+ [Symbol.asyncIterator]() {
+ return this;
+ },
+ }, AsyncIteratorPrototype);
+
+ eventTargetAgnosticAddListener(emitter, event, eventHandler);
+ if (event !== "error" && typeof emitter.on === "function") {
+ emitter.on("error", errorHandler);
+ }
+
+ if (signal) {
+ eventTargetAgnosticAddListener(
+ signal,
+ "abort",
+ abortListener,
+ { once: true },
+ );
+ }
+
+ return iterator;
+
+ function abortListener() {
+ errorHandler(new AbortError());
+ }
+
+ function eventHandler(...args) {
+ const promise = unconsumedPromises.shift();
+ if (promise) {
+ promise.resolve(createIterResult(args, false));
+ } else {
+ unconsumedEvents.push(args);
+ }
+ }
+
+ function errorHandler(err) {
+ finished = true;
+
+ const toError = unconsumedPromises.shift();
+
+ if (toError) {
+ toError.reject(err);
+ } else {
+ // The next time we call next()
+ error = err;
+ }
+
+ iterator.return();
+ }
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-27 07:45:34 +0000