module.exports = function () {
  let emitter = {
    events: { }
  }

  emitter.emit = (event, ...args) => {
    (emitter.events[event] || []).filter(i => i(...args))
  }

  emitter.on = (event, cb) => {
    (emitter.events[event] = emitter.events[event] || []).push(cb)
    return function () {
      emitter.events[event] = emitter.events[event].filter(i => i !== cb)
    }
  }

  return emitter
}

@@ -30,21 +30,14 @@
 %7B%0A  
-let emitter =
+return
  %7B%0A 
@@ -52,32 +52,19 @@
 s: %7B
- 
 %7D
+,
 %0A  
-%7D%0A%0A
   emit
-ter.emit =
  (ev
@@ -76,34 +76,30 @@
 ...args)
- =%3E
  %7B%0A    
-(emitter
+  (this
 .events%5B
@@ -142,25 +142,19 @@
 )%0A  
-%7D%0A%0A  emitter.on =
+  %7D,%0A    on
  (ev
@@ -165,26 +165,22 @@
  cb)
- =%3E
  %7B%0A    
-(emitter
+  (this
 .eve
@@ -184,39 +184,36 @@
 events%5Bevent%5D = 
-emitter
+this
 .events%5Bevent%5D %7C
@@ -235,42 +235,37 @@
     
+  
 return 
-function () %7B%0A      emitter
+() =%3E (%0A        this
 .eve
@@ -277,23 +277,20 @@
 vent%5D = 
-emitter
+this
 .events%5B
@@ -326,30 +326,20 @@
     
-%7D%0A  %7D%0A%0A  return emitter
+  )%0A    %7D%0A  %7D
 %0A%7D%0A

Reduce size to 69 (#30)