src/lib/base/eventemitter3.js
function EE(fn, context, once) {
  this.fn = fn;
  this.context = context;
  this.once = once || false;
}
function EE(fn, context, once) {
  this.fn = fn;
  this.context = context;
  this.once = once || false;
}
function EE ( fn , context , once ) { this . fn = fn ; this . context = context ; this . once = once || false ; }
Representation of a single event listener.

@param {Function} fn The listener function.
@param {*} context The context to invoke the listener with.
@param {boolean} [once=false] Specify if the listener is a one-time listener.
@constructor
@private
Representation of a single event listener .