diff --git a/eventemitter3/eventemitter3-tests.ts b/eventemitter3/eventemitter3-tests.ts
index 6c5733bec7..77d84093cf 100644
--- a/eventemitter3/eventemitter3-tests.ts
+++ b/eventemitter3/eventemitter3-tests.ts
@@ -1,586 +1,117 @@
 ///<reference path="eventemitter3.d.ts" />
-///<reference path="../node/node.d.ts" />
-///<reference path="../mocha/mocha.d.ts" />
 'use strict';
 
 import EventEmitter = require('eventemitter3');
-import util = require('util');
-import * as EventEmitter3ImportedAsES6Module from 'eventemitter3';
 
-declare namespace Assume {
-  interface Class<T> {
-    new(...args: any[]): T;
-  }
-
-  interface Assume<T> {
-    equals(compare: T): Assume<T>;
-    equal(compare: T): Assume<T>;
-    eqls(compare: T): Assume<T>;
-    is: Assume<T>;
-    deep: Assume<T>;
-    to: Assume<T>;
-    either(arr: T[]): Assume<T>;
-    instanceOf(clazz: Class<T>): Assume<T>;
-    a(typeofString: string): Assume<T>;
-  }
-
-  export function assume<T>(input: T): Assume<T>;
-}
-
-let assume = Assume.assume;
-
-class EventEmitterTest {
-    v: EventEmitter3.EventEmitter;
+const eventName = 'test';
+const eventSymbol = Symbol('test');
+const fn = () => console.log(1);
 
+// Extending EventEmitter
+class TestEmitter extends EventEmitter {
     constructor() {
-        this.v = new EventEmitter();
-        this.v = new EventEmitter3ImportedAsES6Module();
-
-        // Some methods are missing or incompatible with current implementation (v4.2.x) of NodeJS.EventEmitter
-        // (e.g. getMaxListenters or listeners)
-        // var n: NodeJS.EventEmitter = this.v;
+        super();
     }
 
-    listeners() {
-        var v1: Function[] = this.v.listeners('click');
-    }
-
-    emit() {
-        var v1: boolean = this.v.emit('click');
-        var v2: boolean = this.v.emit('click', 1);
-        var v3: boolean = this.v.emit('click', 1, '1');
-        var v4: boolean = this.v.emit('click', 1, '1', true);
-        var v5: boolean = this.v.emit('click', 1, '1', true, new Date());
-    }
-
-    on() {
-        var fn = () => console.log(1);
-        var v1: EventEmitter3.EventEmitter = this.v.on('click', fn);
-        var v2: EventEmitter3.EventEmitter = this.v.on('click', fn, this);
-    }
-
-    once() {
-        var fn = () => console.log(1);
-        var v1: EventEmitter3.EventEmitter = this.v.once('click', fn);
-        var v2: EventEmitter3.EventEmitter = this.v.once('click', fn, this);
-    }
-
-    removeListener() {
-        var fn = () => console.log(1);
-        var v1: EventEmitter3.EventEmitter = this.v.removeListener('click', fn);
-        var v2: EventEmitter3.EventEmitter = this.v.removeListener('click', fn, true);
-    }
-
-    removeAllListeners() {
-        var v1: EventEmitter3.EventEmitter = this.v.removeAllListeners('click');
-    }
-
-    off() {
-        var fn = () => console.log(1);
-        var v1: EventEmitter3.EventEmitter = this.v.off('click', fn);
-        var v2: EventEmitter3.EventEmitter = this.v.off('click', fn, true);
-    }
-
-    addListener() {
-        var fn = () => console.log(1);
-        var v1: EventEmitter3.EventEmitter = this.v.addListener('click', fn);
-        var v2: EventEmitter3.EventEmitter = this.v.addListener('click', fn, this);
-    }
-
-    setMaxListeners() {
-        var v1: EventEmitter3.EventEmitter = this.v.setMaxListeners();
+    test() {
+        return this;
     }
 }
 
+const ee: TestEmitter = new TestEmitter();
 
-describe('EventEmitter', function tests() {
-  'use strict';
+// EventEmitter.prefixed
+// should be boolean or string static property
+const prefix = EventEmitter.prefixed;
+if (typeof prefix === 'boolean') {
+    console.log(prefix.valueOf());
+} else {
+    console.log(prefix.length);
+}
 
-  it('exposes a `prefixed` property', function () {
-    assume(EventEmitter.prefixed).is.either([false, '~']);
-  });
-
-  it('inherits when used with require(util).inherits', function () {
-    class Beast extends EventEmitter {
-      /* rawr, i'm a beast */
+// EventEmitter.eventNames()
+// should return array of strings or symbols
+ee.eventNames().every((event) => {
+    if (typeof event === 'symbol') {
+        return false;
+    } else {
+        return event.length > 0;
     }
-
-    class BeastES6 extends EventEmitter3ImportedAsES6Module {
-      /* rawr, i'm a beast */
-    }
-
-    util.inherits(Beast, EventEmitter);
-
-    var moop = new Beast()
-      , meap = new Beast();
-
-    assume(moop).is.instanceOf(Beast);
-    assume(moop).is.instanceOf(EventEmitter);
-
-    moop.listeners();
-    meap.listeners();
-
-    moop.on('data', function () {
-      throw new Error('I should not emit');
-    });
-
-    meap.emit('data', 'rawr');
-    meap.removeListener('foo');
-    meap.removeAllListeners();
-  });
-
-  describe('EventEmitter#emit', function () {
-    it('should return false when there are not events to emit', function () {
-      var e = new EventEmitter();
-
-      assume(e.emit('foo')).equals(false);
-      assume(e.emit('bar')).equals(false);
-    });
-
-    it('emits with context', function (done) {
-      var context = { bar: 'baz' }
-        , e = new EventEmitter();
-
-      e.on('foo', function (bar: string) {
-        assume(bar).equals('bar');
-        assume(this).equals(context);
-
-        done();
-      }, context).emit('foo', 'bar');
-    });
-
-    it('emits with context, multiple arguments (force apply)', function (done) {
-      var context = { bar: 'baz' }
-        , e = new EventEmitter();
-
-      e.on('foo', function (bar: string) {
-        assume(bar).equals('bar');
-        assume(this).equals(context);
-
-        done();
-      }, context).emit('foo', 'bar', 1,2,3,4,5,6,7,8,9,0);
-    });
-
-    it('can emit the function with multiple arguments', function () {
-      var e = new EventEmitter();
-
-      for(var i = 0; i < 100; i++) {
-        (function (j: number) {
-          for (var i = 0, args: number[] = []; i < j; i++) {
-            args.push(j);
-          }
-
-          e.once('args', function () {
-            assume(arguments.length).equals(args.length);
-          });
-
-          e.emit.apply(e, (['args'] as any[]).concat(args));
-        })(i);
-      }
-    });
-
-    it('can emit the function with multiple arguments, multiple listeners', function () {
-      var e = new EventEmitter();
-
-      for(var i = 0; i < 100; i++) {
-        (function (j: number) {
-          for (var i = 0, args: number[] = []; i < j; i++) {
-            args.push(j);
-          }
-
-          e.once('args', function () {
-            assume(arguments.length).equals(args.length);
-          });
-
-          e.once('args', function () {
-            assume(arguments.length).equals(args.length);
-          });
-
-          e.once('args', function () {
-            assume(arguments.length).equals(args.length);
-          });
-
-          e.once('args', function () {
-            assume(arguments.length).equals(args.length);
-          });
-
-          e.emit.apply(e, (['args'] as any[]).concat(args));
-        })(i);
-      }
-    });
-
-    it('emits with context, multiple listeners (force loop)', function () {
-      var e = new EventEmitter();
-
-      e.on('foo', function (bar: string) {
-        assume(this).eqls({ foo: 'bar' });
-        assume(bar).equals('bar');
-      }, { foo: 'bar' });
-
-      e.on('foo', function (bar: string) {
-        assume(this).eqls({ bar: 'baz' });
-        assume(bar).equals('bar');
-      }, { bar: 'baz' });
-
-      e.emit('foo', 'bar');
-    });
-
-    it('emits with different contexts', function () {
-      var e = new EventEmitter()
-        , pattern = '';
-
-      function writer() {
-        pattern += this;
-      }
-
-      e.on('write', writer, 'foo');
-      e.on('write', writer, 'baz');
-      e.once('write', writer, 'bar');
-      e.once('write', writer, 'banana');
-
-      e.emit('write');
-      assume(pattern).equals('foobazbarbanana');
-    });
-
-    it('should return true when there are events to emit', function (done) {
-      var e = new EventEmitter();
-
-      e.on('foo', function () {
-        process.nextTick(done);
-      });
-
-      assume(e.emit('foo')).equals(true);
-      assume(e.emit('foob')).equals(false);
-    });
-
-    it('receives the emitted events', function (done) {
-      var e = new EventEmitter();
-
-      e.on('data', function (a: string, b: EventEmitter3.EventEmitter, c: Date, d: void, undef: void) {
-        assume(a).equals('foo');
-        assume(b).equals(e);
-        assume(c).is.instanceOf(Date);
-        assume(undef).equals(undefined);
-        assume(arguments.length).equals(3);
-
-        done();
-      });
-
-      e.emit('data', 'foo', e, new Date());
-    });
-
-    it('emits to all event listeners', function () {
-      var e = new EventEmitter()
-        , pattern: string[] = [];
-
-      e.on('foo', function () {
-        pattern.push('foo1');
-      });
-
-      e.on('foo', function () {
-        pattern.push('foo2');
-      });
-
-      e.emit('foo');
-
-      assume(pattern.join(';')).equals('foo1;foo2');
-    });
-
-    (function each(keys: string[]) {
-      var key = keys.shift();
-
-      if (!key) return;
-
-      it('can store event which is a known property: '+ key, function (next) {
-        var e = new EventEmitter();
-
-        e.on(key, function (key: string) {
-          assume(key).equals(key);
-          next();
-        }).emit(key, key);
-      });
-
-      each(keys);
-    })([
-      'hasOwnProperty',
-      'constructor',
-      '__proto__',
-      'toString',
-      'toValue',
-      'unwatch',
-      'watch'
-    ]);
-  });
-
-  describe('EventEmitter#listeners', function () {
-    it('returns an empty array if no listeners are specified', function () {
-      var e = new EventEmitter();
-
-      assume(e.listeners('foo')).is.a('array');
-      assume(e.listeners('foo').length).equals(0);
-    });
-
-    it('returns an array of function', function () {
-       var e = new EventEmitter();
-
-       function foo() {}
-
-       e.on('foo', foo);
-       assume(e.listeners('foo')).is.a('array');
-       assume(e.listeners('foo').length).equals(1);
-       assume(e.listeners('foo')).deep.equals([foo]);
-    });
-
-    it('is not vulnerable to modifications', function () {
-      var e = new EventEmitter();
-
-      function foo() {}
-
-      e.on('foo', foo);
-
-      assume(e.listeners('foo')).deep.equals([foo]);
-
-      e.listeners('foo').length = 0;
-      assume(e.listeners('foo')).deep.equals([foo]);
-    });
-
-    it('can return a boolean as indication if listeners exist', function () {
-      var e = new EventEmitter();
-
-      function foo() {}
-
-      e.once('once', foo);
-      e.once('multiple', foo);
-      e.once('multiple', foo);
-      e.on('on', foo);
-      e.on('multi', foo);
-      e.on('multi', foo);
-
-      assume(e.listeners('foo', true)).equals(false);
-      assume(e.listeners('multiple', true)).equals(true);
-      assume(e.listeners('on', true)).equals(true);
-      assume(e.listeners('multi', true)).equals(true);
-
-      e.removeAllListeners();
-
-      assume(e.listeners('multiple', true)).equals(false);
-      assume(e.listeners('on', true)).equals(false);
-      assume(e.listeners('multi', true)).equals(false);
-    });
-  });
-
-  describe('EventEmitter#once', function () {
-    it('only emits it once', function () {
-      var e = new EventEmitter()
-        , calls = 0;
-
-      e.once('foo', function () {
-        calls++;
-      });
-
-      e.emit('foo');
-      e.emit('foo');
-      e.emit('foo');
-      e.emit('foo');
-      e.emit('foo');
-
-      assume(e.listeners('foo').length).equals(0);
-      assume(calls).equals(1);
-    });
-
-    it('only emits once if emits are nested inside the listener', function () {
-      var e = new EventEmitter()
-        , calls = 0;
-
-      e.once('foo', function () {
-        calls++;
-        e.emit('foo');
-      });
-
-      e.emit('foo');
-      assume(e.listeners('foo').length).equals(0);
-      assume(calls).equals(1);
-    });
-
-    it('only emits once for multiple events', function () {
-      var e = new EventEmitter()
-        , multi = 0
-        , foo = 0
-        , bar = 0;
-
-      e.once('foo', function () {
-        foo++;
-      });
-
-      e.once('foo', function () {
-        bar++;
-      });
-
-      e.on('foo', function () {
-        multi++;
-      });
-
-      e.emit('foo');
-      e.emit('foo');
-      e.emit('foo');
-      e.emit('foo');
-      e.emit('foo');
-
-      assume(e.listeners('foo').length).equals(1);
-      assume(multi).equals(5);
-      assume(foo).equals(1);
-      assume(bar).equals(1);
-    });
-
-    it('only emits once with context', function (done) {
-      var context = { foo: 'bar' }
-        , e = new EventEmitter();
-
-      e.once('foo', function (bar: string) {
-        assume(this).equals(context);
-        assume(bar).equals('bar');
-
-        done();
-      }, context).emit('foo', 'bar');
-    });
-  });
-
-  describe('EventEmitter#removeListener', function () {
-    it('should only remove the event with the specified function', function () {
-      var e = new EventEmitter();
-
-      function bar() {}
-      e.on('foo', function () {});
-      e.on('bar', function () {});
-      e.on('bar', bar);
-
-      assume(e.removeListener('foo', bar)).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.listeners('bar').length).equals(2);
-
-      assume(e.removeListener('foo')).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-      assume(e.listeners('bar').length).equals(2);
-
-      assume(e.removeListener('bar', bar)).equals(e);
-      assume(e.listeners('bar').length).equals(1);
-      assume(e.removeListener('bar')).equals(e);
-      assume(e.listeners('bar').length).equals(0);
-    });
-
-    it('should only remove once events when using the once flag', function () {
-      var e = new EventEmitter();
-
-      function foo() {}
-      e.on('foo', foo);
-
-      assume(e.removeListener('foo', function () {}, undefined, true)).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.removeListener('foo', foo, undefined, true)).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.removeListener('foo', foo)).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-
-      e.on('foo', foo);
-      e.once('foo', foo);
-
-      assume(e.removeListener('foo', function () {}, undefined, true)).equals(e);
-      assume(e.listeners('foo').length).equals(2);
-      assume(e.removeListener('foo', foo, undefined, true)).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-
-      e.once('foo', foo);
-
-      assume(e.removeListener('foo', foo)).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-    });
-
-    it('should only remove listeners matching the correct context', function () {
-      var e = new EventEmitter()
-        , context = { foo: 'bar' };
-
-      function foo() {}
-      function bar() {}
-      e.on('foo', foo, context);
-
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.removeListener('foo', function () {}, context)).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.removeListener('foo', foo, { baz: 'quux' })).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.removeListener('foo', foo, context)).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-
-      e.on('foo', foo, context);
-      e.on('foo', bar);
-
-      assume(e.listeners('foo').length).equals(2);
-      assume(e.removeListener('foo', foo, { baz: 'quux' })).equals(e);
-      assume(e.listeners('foo').length).equals(2);
-      assume(e.removeListener('foo', foo, context)).equals(e);
-      assume(e.listeners('foo').length).equals(1);
-      assume(e.listeners('foo')[0]).equals(bar);
-
-      e.on('foo', foo, context);
-
-      assume(e.listeners('foo').length).equals(2);
-      assume(e.removeAllListeners('foo')).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-    });
-  });
-
-  describe('EventEmitter#removeAllListeners', function () {
-    it('removes all events for the specified events', function () {
-      var e = new EventEmitter();
-
-      e.on('foo', function () { throw new Error('oops'); });
-      e.on('foo', function () { throw new Error('oops'); });
-      e.on('bar', function () { throw new Error('oops'); });
-      e.on('aaa', function () { throw new Error('oops'); });
-
-      assume(e.removeAllListeners('foo')).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-      assume(e.listeners('bar').length).equals(1);
-      assume(e.listeners('aaa').length).equals(1);
-
-      assume(e.removeAllListeners('bar')).equals(e);
-      assume(e.removeAllListeners('aaa')).equals(e);
-
-      assume(e.emit('foo')).equals(false);
-      assume(e.emit('bar')).equals(false);
-      assume(e.emit('aaa')).equals(false);
-    });
-
-    it('just nukes the fuck out of everything', function () {
-      var e = new EventEmitter();
-
-      e.on('foo', function () { throw new Error('oops'); });
-      e.on('foo', function () { throw new Error('oops'); });
-      e.on('bar', function () { throw new Error('oops'); });
-      e.on('aaa', function () { throw new Error('oops'); });
-
-      assume(e.removeAllListeners()).equals(e);
-      assume(e.listeners('foo').length).equals(0);
-      assume(e.listeners('bar').length).equals(0);
-      assume(e.listeners('aaa').length).equals(0);
-
-      assume(e.emit('foo')).equals(false);
-      assume(e.emit('bar')).equals(false);
-      assume(e.emit('aaa')).equals(false);
-    });
-  });
-
-  describe('#setMaxListeners', function () {
-    it('is a function', function () {
-      var e = new EventEmitter();
-
-      assume(e.setMaxListeners).is.a('function');
-    });
-
-    it('returns self when called', function () {
-      var e = new EventEmitter();
-
-      assume(e.setMaxListeners()).to.equal(e);
-    });
-  });
 });
+
+// EventEmitter.listeners()
+// should return array of functions
+ee.listeners(eventName).map((listener) => {
+    return listener.bind(this);
+});
+// should accept symbol as event name
+ee.listeners(eventSymbol).map((listener) => {
+    return listener.bind(this);
+});
+// should return boolean with 'exists' flag
+const hasListeners: boolean = ee.listeners(eventName, true);
+
+// EventEmitter.emit()
+// should support any number of arguments
+ee.emit(eventName, 1, true, {}, [], 'test', Symbol(), null);
+// should accept symbol as event name
+ee.emit(eventSymbol);
+
+// EventEmitter.addListener() and EventEmitter.on()
+// should accept function
+ee.on(eventName, fn);
+ee.addListener(eventName, fn);
+// should accept optional context argument
+ee.on(eventName, fn, this);
+ee.addListener(eventName, fn, this);
+// should accept symbol as event name
+ee.on(eventSymbol, fn);
+ee.addListener(eventSymbol, fn);
+// should support fluent interface
+ee.on(eventSymbol, fn).test();
+ee.addListener(eventSymbol, fn).test();
+
+// EventEmitter.once()
+// should accept event name and function
+ee.once(eventName, fn);
+// should accept optional context argument
+ee.once(eventName, fn, this);
+ee.once(eventName, fn, {});
+// should accept symbol as event name
+ee.once(eventSymbol, fn);
+// should support fluent interface
+ee.once(eventSymbol, fn).test();
+
+// EventEmitter.removeListener() and EventEmitter.off()
+// should accept event name
+ee.removeListener(eventName);
+ee.off(eventName);
+// should accept optional function
+ee.removeListener(eventName, fn);
+ee.off(eventName, fn);
+// should accept optional context argument
+ee.removeListener(eventName, fn, {});
+ee.off(eventName, fn, {});
+// should accept optional boolean flag for removing listeners added with `EventEmitter.once()`
+ee.removeListener(eventName, fn, null, true);
+ee.off(eventName, fn, null, true);
+// should accept symbol as event name
+ee.removeListener(eventSymbol);
+ee.off(eventSymbol);
+// should support fluent interface
+ee.removeListener(eventName).test();
+ee.off(eventName).test();
+
+// EventEmitter.removeAllListeners()
+// should not require any arguments
+ee.removeAllListeners();
+// should accept optional event name
+ee.removeAllListeners(eventName);
+// should accept symbol as event name
+ee.removeAllListeners(eventSymbol);
+// should support fluent interface
+ee.removeAllListeners(eventName).test();
+
+// EventEmitter.setMaxListeners()
+// should support fluent interface
+ee.setMaxListeners().test();
diff --git a/eventemitter3/eventemitter3-tests.ts.tscparams b/eventemitter3/eventemitter3-tests.ts.tscparams
new file mode 100644
index 0000000000..30c9419a57
--- /dev/null
+++ b/eventemitter3/eventemitter3-tests.ts.tscparams
@@ -0,0 +1 @@
+-m commonjs
diff --git a/eventemitter3/eventemitter3.d.ts b/eventemitter3/eventemitter3.d.ts
index 0d692b8247..96af62c94b 100644
--- a/eventemitter3/eventemitter3.d.ts
+++ b/eventemitter3/eventemitter3.d.ts
@@ -1,123 +1,109 @@
-// Type definitions for EventEmitter3 1.1.1
+// Type definitions for EventEmitter3 1.2.0
 // Project: https://github.com/primus/eventemitter3
-// Definitions by: Yuichi Murata <https://github.com/mrk21>, Leon Yu <https://github.com/leonyu>
+// Definitions by: Yuichi Murata <https://github.com/mrk21>, Leon Yu <https://github.com/leonyu>, Boriss Nazarovs <https://github.com/Stubb0rn>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 declare namespace EventEmitter3 {
-    interface EventEmitter3Static {
-        new (): EventEmitter;
-        prefixed: string | boolean;
-    }
+    /**
+     * Minimal EventEmitter interface that is molded against the Node.js
+     * EventEmitter interface.
+     */
     class EventEmitter {
-        /**
-         * Minimal EventEmitter interface that is molded against the Node.js
-         * EventEmitter interface.
-         *
-         * @constructor
-         * @api public
-         */
         constructor();
 
         /**
-         * Return a list of assigned event listeners.
+         * Return an array listing the events for which the emitter has registered listeners.
          *
-         * @param {String} event The events that should be listed.
-         * @returns {Array}
-         * @api public
+         * @returns {(string|symbol)[]}
          */
-        listeners(event?: string): Function[];
+        eventNames(): (string|symbol)[];
 
         /**
-         * Return a list of assigned event listeners.
+         * Return the listeners registered for a given event.
          *
-         * @param {String} event The events that should be listed.
-         * @param {Boolean} exists We only need to know if there are listeners.
-         * @returns {Boolean}
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @returns {Function[]}
          */
-        listeners(event: string, param: boolean): boolean;
+        listeners(event: string|symbol): Function[];
 
         /**
-         * Emit an event to all registered event listeners.
+         * Check if there listeners for a given event.
+         * If `exists` argument is not `true` lists listeners.
          *
-         * @param {String} event The name of the event.
-         * @returns {Boolean} Indication if we've emitted an event.
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @param {boolean} exists Only check if there are listeners.
+         * @returns {boolean}
          */
-        emit(event: string, ...args: any[]): boolean;
+        listeners(event: string|symbol, exists: boolean): boolean;
 
         /**
-         * Register a new EventListener for the given event.
+         * Calls each of the listeners registered for a given event.
          *
-         * @param {String} event Name of the event.
-         * @param {Function} fn Callback function.
-         * @param {Mixed} [context=this] The context of the function.
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @param {...*} args Arguments that are passed to registered listeners
+         * @returns {boolean} `true` if the event had listeners, else `false`.
          */
-        on(event: string, fn: Function, context?: any): EventEmitter;
+        emit(event: string|symbol, ...args: any[]): boolean;
 
         /**
-         * Add an EventListener that's only called once.
+         * Add a listener for a given event.
          *
-         * @param {String} event Name of the event.
-         * @param {Function} fn Callback function.
-         * @param {Mixed} [context=this] The context of the function.
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @param {Function} fn The listener function.
+         * @param {*} [context=this] The context to invoke the listener with.
+         * @returns {EventEmitter} `this`.
          */
-        once(event: string, fn: Function, context?: any): EventEmitter;
+        on(event: string|symbol, fn: Function, context?: any): this;
 
         /**
-         * Remove event listeners.
+         * Add a one-time listener for a given event.
          *
-         * @param {String} event The event we want to remove.
-         * @param {Function} fn The listener that we need to find.
-         * @param {Mixed} context Only remove listeners matching this context.
-         * @param {Boolean} once Only remove once listeners.
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @param {Function} fn The listener function.
+         * @param {*} [context=this] The context to invoke the listener with.
+         * @returns {EventEmitter} `this`.
          */
-        removeListener(event: string, fn?: Function, context?: any, once?: boolean): EventEmitter;
+        once(event: string|symbol, fn: Function, context?: any): this;
 
         /**
-         * Remove all listeners or only the listeners for the specified event.
+         * Remove the listeners of a given event.
          *
-         * @param {String} event The event want to remove all listeners for.
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @param {Function} fn Only remove the listeners that match this function.
+         * @param {*} context Only remove the listeners that have this context.
+         * @param {boolean} once Only remove one-time listeners.
+         * @returns {EventEmitter} `this`.
          */
-        removeAllListeners(event?: string): EventEmitter;
+        removeListener(event: string|symbol, fn?: Function, context?: any, once?: boolean): this;
 
         /**
-         * Remove event listeners.
+         * Remove all listeners, or those of the specified event.
          *
-         * @param {String} event The event we want to remove.
-         * @param {Function} fn The listener that we need to find.
-         * @param {Mixed} context Only remove listeners matching this context.
-         * @param {Boolean} once Only remove once listeners.
-         * @api public
+         * @param {(string|symbol)} event The event name.
+         * @returns {EventEmitter} `this`.
          */
-        off(event: string, fn?: Function, context?: any, once?: boolean): EventEmitter;
+        removeAllListeners(event?: string|symbol): this;
 
         /**
-         * Register a new EventListener for the given event.
-         *
-         * @param {String} event Name of the event.
-         * @param {Function} fn Callback function.
-         * @param {Mixed} [context=this] The context of the function.
-         * @api public
+         * Alias method for `removeListener`
          */
-        addListener(event: string, fn: Function, context?: any): EventEmitter;
+        off(event: string|symbol, fn?: Function, context?: any, once?: boolean): this;
+
+        /**
+         * Alias method for `on`
+         */
+        addListener(event: string|symbol, fn: Function, context?: any): this;
 
         /**
          * This function doesn't apply anymore.
          * @deprecated
          */
-        setMaxListeners(): EventEmitter;
+        setMaxListeners(): this;
+
+        static prefixed: string|boolean;
     }
 }
 
 declare module 'eventemitter3' {
-    //
-    // Expose the module.
-    //
-    var EventEmitter3: EventEmitter3.EventEmitter3Static;
-    export = EventEmitter3;
+    export = EventEmitter3.EventEmitter;
 }