Slightly customize the `events` polyfill so it uses ESM

1 files changed, 522 insertions, 1 deletions

diff --git a/src/node-fallbacks/events.js b/src/node-fallbacks/events.js
index c804909af..e5b3d28df 100644
--- a/src/node-fallbacks/events.js
+++ b/src/node-fallbacks/events.js
@@ -1 +1,522 @@
-export * from "events";
+// 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";
+
+var R = typeof Reflect === "object" ? Reflect : null;
+var ReflectApply =
+  R && typeof R.apply === "function"
+    ? R.apply
+    : function ReflectApply(target, receiver, args) {
+        return Function.prototype.apply.call(target, receiver, args);
+      };
+
+var ReflectOwnKeys;
+if (R && typeof R.ownKeys === "function") {
+  ReflectOwnKeys = R.ownKeys;
+} else if (Object.getOwnPropertySymbols) {
+  ReflectOwnKeys = function ReflectOwnKeys(target) {
+    return Object.getOwnPropertyNames(target).concat(
+      Object.getOwnPropertySymbols(target)
+    );
+  };
+} else {
+  ReflectOwnKeys = function ReflectOwnKeys(target) {
+    return Object.getOwnPropertyNames(target);
+  };
+}
+
+function ProcessEmitWarning(warning) {
+  if (console && console.warn) console.warn(warning);
+}
+
+var NumberIsNaN =
+  Number.isNaN ||
+  function NumberIsNaN(value) {
+    return value !== value;
+  };
+
+function EventEmitter() {
+  EventEmitter.init.call(this);
+}
+
+// Backwards-compat with node 0.10.x
+EventEmitter.EventEmitter = EventEmitter;
+
+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.
+var defaultMaxListeners = 10;
+
+function checkListener(listener) {
+  if (typeof listener !== "function") {
+    throw new TypeError(
+      'The "listener" argument must be of type Function. Received type ' +
+        typeof listener
+    );
+  }
+}
+
+Object.defineProperty(EventEmitter, "defaultMaxListeners", {
+  enumerable: true,
+  get: function () {
+    return defaultMaxListeners;
+  },
+  set: function (arg) {
+    if (typeof arg !== "number" || arg < 0 || NumberIsNaN(arg)) {
+      throw new RangeError(
+        'The value of "defaultMaxListeners" is out of range. It must be a non-negative number. Received ' +
+          arg +
+          "."
+      );
+    }
+    defaultMaxListeners = arg;
+  },
+});
+
+EventEmitter.init = function () {
+  if (
+    this._events === undefined ||
+    this._events === Object.getPrototypeOf(this)._events
+  ) {
+    this._events = Object.create(null);
+    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 || NumberIsNaN(n)) {
+    throw new RangeError(
+      'The value of "n" is out of range. It must be a non-negative number. Received ' +
+        n +
+        "."
+    );
+  }
+  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);
+};
+
+EventEmitter.prototype.emit = function emit(type) {
+  var args = [];
+  for (var i = 1; i < arguments.length; i++) args.push(arguments[i]);
+  var doError = type === "error";
+
+  var events = this._events;
+  if (events !== undefined) doError = doError && events.error === undefined;
+  else if (!doError) return false;
+
+  // If there is no 'error' event listener then throw.
+  if (doError) {
+    var er;
+    if (args.length > 0) er = args[0];
+    if (er instanceof Error) {
+      // 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
+    }
+    // At least give some kind of context to the user
+    var err = new Error(
+      "Unhandled error." + (er ? " (" + er.message + ")" : "")
+    );
+    err.context = er;
+    throw err; // Unhandled 'error' event
+  }
+
+  var handler = events[type];
+
+  if (handler === undefined) return false;
+
+  if (typeof handler === "function") {
+    ReflectApply(handler, this, args);
+  } else {
+    var len = handler.length;
+    var listeners = arrayClone(handler, len);
+    for (var i = 0; i < len; ++i) ReflectApply(listeners[i], this, args);
+  }
+
+  return true;
+};
+
+function _addListener(target, type, listener, prepend) {
+  var m;
+  var events;
+  var 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.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.
+    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];
+      // 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
+      var w = new Error(
+        "Possible EventEmitter memory leak detected. " +
+          existing.length +
+          " " +
+          String(type) +
+          " listeners " +
+          "added. Use emitter.setMaxListeners() to " +
+          "increase limit"
+      );
+      w.name = "MaxListenersExceededWarning";
+      w.emitter = target;
+      w.type = type;
+      w.count = existing.length;
+      ProcessEmitWarning(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 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) {
+  var state = {
+    fired: false,
+    wrapFn: undefined,
+    target: target,
+    type: type,
+    listener: listener,
+  };
+  var wrapped = onceWrapper.bind(state);
+  wrapped.listener = listener;
+  state.wrapFn = wrapped;
+  return wrapped;
+}
+
+EventEmitter.prototype.once = function once(type, listener) {
+  checkListener(listener);
+  this.on(type, _onceWrap(this, type, listener));
+  return this;
+};
+
+EventEmitter.prototype.prependOnceListener = function prependOnceListener(
+  type,
+  listener
+) {
+  checkListener(listener);
+  this.prependListener(type, _onceWrap(this, type, listener));
+  return this;
+};
+
+// Emits a 'removeListener' event if and only if the listener was removed.
+EventEmitter.prototype.removeListener = function removeListener(
+  type,
+  listener
+) {
+  var list, events, position, i, originalListener;
+
+  checkListener(listener);
+
+  events = this._events;
+  if (events === undefined) return this;
+
+  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") {
+    position = -1;
+
+    for (i = list.length - 1; i >= 0; i--) {
+      if (list[i] === listener || list[i].listener === listener) {
+        originalListener = list[i].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, originalListener || listener);
+  }
+
+  return this;
+};
+
+EventEmitter.prototype.off = EventEmitter.prototype.removeListener;
+
+EventEmitter.prototype.removeAllListeners = function removeAllListeners(type) {
+  var listeners, events, i;
+
+  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) {
+    var keys = Object.keys(events);
+    var key;
+    for (i = 0; i < keys.length; ++i) {
+      key = keys[i];
+      if (key === "removeListener") continue;
+      this.removeAllListeners(key);
+    }
+    this.removeAllListeners("removeListener");
+    this._events = Object.create(null);
+    this._eventsCount = 0;
+    return this;
+  }
+
+  listeners = events[type];
+
+  if (typeof listeners === "function") {
+    this.removeListener(type, listeners);
+  } else if (listeners !== undefined) {
+    // LIFO order
+    for (i = listeners.length - 1; i >= 0; i--) {
+      this.removeListener(type, listeners[i]);
+    }
+  }
+
+  return this;
+};
+
+function _listeners(target, type, unwrap) {
+  var events = target._events;
+
+  if (events === undefined) return [];
+
+  var evlistener = events[type];
+  if (evlistener === undefined) return [];
+
+  if (typeof evlistener === "function")
+    return unwrap ? [evlistener.listener || evlistener] : [evlistener];
+
+  return unwrap
+    ? unwrapListeners(evlistener)
+    : arrayClone(evlistener, evlistener.length);
+}
+
+EventEmitter.prototype.listeners = function listeners(type) {
+  return _listeners(this, type, true);
+};
+
+EventEmitter.prototype.rawListeners = function rawListeners(type) {
+  return _listeners(this, type, false);
+};
+
+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) {
+  var events = this._events;
+
+  if (events !== undefined) {
+    var evlistener = events[type];
+
+    if (typeof evlistener === "function") {
+      return 1;
+    } else if (evlistener !== undefined) {
+      return evlistener.length;
+    }
+  }
+
+  return 0;
+}
+
+EventEmitter.prototype.eventNames = function eventNames() {
+  return this._eventsCount > 0 ? ReflectOwnKeys(this._events) : [];
+};
+
+function arrayClone(arr, n) {
+  var copy = new Array(n);
+  for (var i = 0; i < n; ++i) copy[i] = arr[i];
+  return copy;
+}
+
+function spliceOne(list, index) {
+  for (; index + 1 < list.length; index++) list[index] = list[index + 1];
+  list.pop();
+}
+
+function unwrapListeners(arr) {
+  var ret = new Array(arr.length);
+  for (var i = 0; i < ret.length; ++i) {
+    ret[i] = arr[i].listener || arr[i];
+  }
+  return ret;
+}
+
+function once(emitter, name) {
+  return new Promise(function (resolve, reject) {
+    function errorListener(err) {
+      emitter.removeListener(name, resolver);
+      reject(err);
+    }
+
+    function resolver() {
+      if (typeof emitter.removeListener === "function") {
+        emitter.removeListener("error", errorListener);
+      }
+      resolve([].slice.call(arguments));
+    }
+
+    eventTargetAgnosticAddListener(emitter, name, resolver, { once: true });
+    if (name !== "error") {
+      addErrorHandlerIfEventEmitter(emitter, errorListener, { once: true });
+    }
+  });
+}
+
+function addErrorHandlerIfEventEmitter(emitter, handler, flags) {
+  if (typeof emitter.on === "function") {
+    eventTargetAgnosticAddListener(emitter, "error", handler, flags);
+  }
+}
+
+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 for `error` events here.
+    emitter.addEventListener(name, function wrapListener(arg) {
+      // IE does not have builtin `{ once: true }` support so we
+      // have to do it manually.
+      if (flags.once) {
+        emitter.removeEventListener(name, wrapListener);
+      }
+      listener(arg);
+    });
+  } else {
+    throw new TypeError(
+      'The "emitter" argument must be of type EventEmitter. Received type ' +
+        typeof emitter
+    );
+  }
+}
+
+export default EventEmitter;
+export { once };
+export { EventEmitter };
+export var prototype = EventEmitter.prototype;