diff --git a/lib/aee.js b/lib/async-emitter.js
similarity index 62%
rename from lib/aee.js
rename to lib/async-emitter.js
index 25b0e2cb..aeab165c 100644
--- a/lib/aee.js
+++ b/lib/async-emitter.js
@@ -2,7 +2,7 @@
 
 const { iter } = require('@metarhia/common');
 
-class AsyncEventEmitter {
+class AsyncEmitter {
   constructor() {
     this.events = new Map();
     this.wrappers = new Map();
@@ -18,12 +18,18 @@ class AsyncEventEmitter {
   }
 
   once(name, fn) {
+    if (fn === undefined) {
+      return new Promise(resolve => {
+        this.once(name, resolve);
+      });
+    }
     const wrapper = (...args) => {
       this.remove(name, wrapper);
       return fn(...args);
     };
     this.wrappers.set(fn, wrapper);
     this.on(name, wrapper);
+    return undefined;
   }
 
   async emit(name, ...args) {
@@ -35,20 +41,31 @@ class AsyncEventEmitter {
   }
 
   remove(name, fn) {
-    const event = this.events.get(name);
+    const { events, wrappers } = this;
+    const event = events.get(name);
     if (!event) return;
     if (event.has(fn)) event.delete(fn);
-    const wrapper = this.wrappers.get(fn);
+    const wrapper = wrappers.get(fn);
     if (wrapper) {
-      this.wrappers.delete(fn);
+      wrappers.delete(fn);
       event.delete(wrapper);
     }
-    if (event.size === 0) this.events.delete(name);
+    if (event.size === 0) events.delete(name);
   }
 
   clear(name) {
-    if (name) this.events.delete(name);
-    else this.events.clear();
+    const { events, wrappers } = this;
+    if (!name) {
+      events.clear();
+      wrappers.clear();
+      return;
+    }
+    const event = events.get(name);
+    if (!event) return;
+    for (const [fn, wrapper] of wrappers.entries()) {
+      if (event.has(wrapper)) wrappers.delete(fn);
+    }
+    events.delete(name);
   }
 
   count(name) {
@@ -66,4 +83,4 @@ class AsyncEventEmitter {
   }
 }
 
-module.exports = { AsyncEventEmitter };
+module.exports = { AsyncEmitter };
diff --git a/metasync.js b/metasync.js
index 5d9a293f..e3f644c5 100644
--- a/metasync.js
+++ b/metasync.js
@@ -16,7 +16,7 @@ const submodules = [
   'poolify', // Create pool from factory
   'queue', // Concurrent queue
   'throttle', // Throttling utilities
-  'aee', // AsyncEventEmitter
+  'async-emitter', // AsyncEmitter
 ].map(path => require('./lib/' + path));
 
 if (nodeVerion >= 10) {
diff --git a/test/aee.js b/test/aee.js
deleted file mode 100644
index 6e0a9635..00000000
--- a/test/aee.js
+++ /dev/null
@@ -1,192 +0,0 @@
-'use strict';
-
-const { AsyncEventEmitter } = require('..');
-const metatests = require('metatests');
-
-metatests.test('AsyncEventEmitter on/emit', async test => {
-  const ee = new AsyncEventEmitter();
-  let emitted = false;
-
-  ee.on('e1', async (a, b, c, d) => {
-    test.strictSame(a, 1);
-    test.strictSame(b, 2);
-    test.strictSame(c, 3);
-    test.strictSame(d, 4);
-    emitted = true;
-  });
-
-  await ee.emit('e1', 1, 2, 3, 4);
-
-  test.strictSame(emitted, true);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter once', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-
-  ee.once('e1', async () => {
-    count++;
-  });
-
-  ee.once('e1', async () => {
-    count++;
-  });
-
-  ee.emit('e1');
-  ee.emit('e1');
-
-  test.strictSame(count, 2);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter remove', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-
-  const fn = async () => {
-    count++;
-  };
-
-  ee.on('e1', fn);
-  ee.emit('e1');
-  ee.remove('e1', fn);
-  ee.emit('e1');
-
-  test.strictSame(count, 1);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter remove once', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-
-  const fn = async () => {
-    count++;
-  };
-
-  ee.on('e1', fn);
-  ee.once('e1', fn);
-  ee.remove('e1', fn);
-  ee.emit('e1');
-
-  test.strictSame(count, 0);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter count', async test => {
-  const ee = new AsyncEventEmitter();
-
-  ee.on('e1', async () => {});
-  ee.on('e1', async () => {});
-
-  test.strictSame(ee.count('e1'), 2);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter clear all', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-
-  ee.on('e1', async () => {
-    count++;
-  });
-
-  ee.clear();
-  ee.emit('e1');
-
-  test.strictSame(count, 0);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter clear by name', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-
-  ee.on('e1', async () => {
-    count++;
-  });
-
-  ee.clear('e1');
-  ee.emit('e1');
-
-  test.strictSame(count, 0);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter names', async test => {
-  const ee = new AsyncEventEmitter();
-
-  ee.on('e1', () => {});
-  ee.on('e1', () => {});
-  ee.on('e2', () => {});
-  ee.on('e3', () => {});
-
-  test.strictSame(ee.names(), ['e1', 'e2', 'e3']);
-  test.end();
-});
-
-metatests.test('AsyncEventEmitter listeners', async test => {
-  const ee = new AsyncEventEmitter();
-
-  ee.on('e1', () => {});
-  ee.on('e1', () => {});
-  ee.on('e2', () => {});
-  ee.on('e3', () => {});
-
-  test.strictSame(ee.listeners('e1').size, 2);
-  test.end();
-});
-
-metatests.test('await AsyncEventEmitter', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-
-  ee.on('e1', async () => {
-    count += 1;
-  });
-
-  await ee.emit('e1');
-
-  test.strictSame(count, 1);
-  test.end();
-});
-
-metatests.test('await multiple listeners AsyncEventEmitter', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-  ee.on('e1', async () => {
-    count += 1;
-  });
-
-  ee.on('e1', async () => {
-    count += 10;
-  });
-
-  ee.on('e1', async () => {
-    count += 100;
-  });
-
-  await ee.emit('e1');
-
-  test.strictSame(count, 111);
-  test.end();
-});
-
-metatests.test('await multiple events AsyncEventEmitter', async test => {
-  const ee = new AsyncEventEmitter();
-  let count = 0;
-  ee.on('e1', async () => {
-    count += 1;
-  });
-
-  ee.on('e2', async () => {
-    count += 10;
-  });
-
-  await ee.emit('e1');
-  await ee.emit('e2');
-
-  test.strictSame(count, 11);
-  test.end();
-});
diff --git a/test/async-emitter.js b/test/async-emitter.js
new file mode 100644
index 00000000..3be2e14e
--- /dev/null
+++ b/test/async-emitter.js
@@ -0,0 +1,221 @@
+'use strict';
+
+const { AsyncEmitter } = require('..');
+const metatests = require('metatests');
+
+metatests.test('AsyncEmitter on/emit', async test => {
+  const ae = new AsyncEmitter();
+  let emitted = false;
+
+  ae.on('e1', async (a, b, c, d) => {
+    test.strictSame(a, 1);
+    test.strictSame(b, 2);
+    test.strictSame(c, 3);
+    test.strictSame(d, 4);
+    emitted = true;
+  });
+
+  await ae.emit('e1', 1, 2, 3, 4);
+
+  test.strictSame(emitted, true);
+  test.end();
+});
+
+metatests.test('AsyncEmitter once', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  ae.once('e1', async () => {
+    count++;
+  });
+
+  ae.once('e1', async () => {
+    count++;
+  });
+
+  ae.emit('e1');
+  ae.emit('e1');
+
+  test.strictSame(count, 2);
+  test.end();
+});
+
+metatests.test('AsyncEmitter await once', async test => {
+  const ae = new AsyncEmitter();
+
+  setTimeout(() => {
+    ae.emit('e1');
+  }, 0);
+
+  await ae.once('e1');
+
+  test.end();
+});
+
+metatests.test('AsyncEmitter remove', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  const fn = async () => {
+    count++;
+  };
+
+  ae.on('e1', fn);
+  ae.emit('e1');
+  ae.remove('e1', fn);
+  ae.emit('e1');
+
+  test.strictSame(count, 1);
+  test.end();
+});
+
+metatests.test('AsyncEmitter remove once', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  const fn = async () => {
+    count++;
+  };
+
+  ae.on('e1', fn);
+  ae.once('e1', fn);
+  ae.remove('e1', fn);
+  ae.emit('e1');
+
+  test.strictSame(count, 0);
+  test.end();
+});
+
+metatests.test('AsyncEmitter count', async test => {
+  const ae = new AsyncEmitter();
+
+  ae.on('e1', async () => {});
+  ae.on('e1', async () => {});
+
+  test.strictSame(ae.count('e1'), 2);
+  test.end();
+});
+
+metatests.test('AsyncEmitter clear all', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  ae.on('e1', async () => {
+    count++;
+  });
+
+  ae.clear();
+  ae.emit('e1');
+
+  test.strictSame(count, 0);
+  test.end();
+});
+
+metatests.test('AsyncEmitter clear by name', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  ae.on('e1', async () => {
+    count++;
+  });
+
+  ae.clear('e1');
+  ae.emit('e1');
+
+  test.strictSame(count, 0);
+  test.end();
+});
+
+metatests.test('AsyncEmitter clear once', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  ae.once('e1', async () => {
+    count++;
+  });
+
+  ae.clear('e1');
+  ae.emit('e1');
+
+  test.strictSame(count, 0);
+  test.strictSame(ae.wrappers.size, 0);
+  test.strictSame(ae.events.size, 0);
+  test.end();
+});
+
+metatests.test('AsyncEmitter names', async test => {
+  const ae = new AsyncEmitter();
+
+  ae.on('e1', () => {});
+  ae.on('e1', () => {});
+  ae.on('e2', () => {});
+  ae.on('e3', () => {});
+
+  test.strictSame(ae.names(), ['e1', 'e2', 'e3']);
+  test.end();
+});
+
+metatests.test('AsyncEmitter listeners', async test => {
+  const ae = new AsyncEmitter();
+
+  ae.on('e1', () => {});
+  ae.on('e1', () => {});
+  ae.on('e2', () => {});
+  ae.on('e3', () => {});
+
+  test.strictSame(ae.listeners('e1').size, 2);
+  test.end();
+});
+
+metatests.test('await AsyncEmitter', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+
+  ae.on('e1', async () => {
+    count += 1;
+  });
+
+  await ae.emit('e1');
+
+  test.strictSame(count, 1);
+  test.end();
+});
+
+metatests.test('await multiple listeners AsyncEmitter', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+  ae.on('e1', async () => {
+    count += 1;
+  });
+
+  ae.on('e1', async () => {
+    count += 10;
+  });
+
+  ae.on('e1', async () => {
+    count += 100;
+  });
+
+  await ae.emit('e1');
+
+  test.strictSame(count, 111);
+  test.end();
+});
+
+metatests.test('await multiple events AsyncEmitter', async test => {
+  const ae = new AsyncEmitter();
+  let count = 0;
+  ae.on('e1', async () => {
+    count += 1;
+  });
+
+  ae.on('e2', async () => {
+    count += 10;
+  });
+
+  await ae.emit('e1');
+  await ae.emit('e2');
+
+  test.strictSame(count, 11);
+  test.end();
+});