events: extract listener check as a function

ZYSzys · codebytere · commit be56fb7ab91f · 2019-01-28T21:54:52.000-08:00
PR-URL: #24303 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de> Reviewed-By: Denys Otrishko <shishugi@gmail.com> Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com> Reviewed-By: James M Snell <jasnell@gmail.com>
diff --git a/lib/events.js b/lib/events.js
@@ -48,6 +48,13 @@ function lazyErrors(){
 return errors;
 }
 
+function checkListener(listener){
+ if (typeof listener !== 'function'){
+ const errors = lazyErrors();
+ throw new errors.ERR_INVALID_ARG_TYPE('listener', 'Function', listener);
+ }
+}
+
 Object.defineProperty(EventEmitter, 'defaultMaxListeners',{
 enumerable: true,
 get: function(){
@@ -195,10 +202,7 @@ function _addListener(target, type, listener, prepend){
 var events;
 var existing;
 
- if (typeof listener !== 'function'){
- const errors = lazyErrors();
- throw new errors.ERR_INVALID_ARG_TYPE('listener', 'Function', listener);
- }
+ checkListener(listener);
 
 events = target._events;
 if (events === undefined){
@@ -283,20 +287,16 @@ function _onceWrap(target, type, listener){
 }
 
 EventEmitter.prototype.once = function once(type, listener){
- if (typeof listener !== 'function'){
- const errors = lazyErrors();
- throw new errors.ERR_INVALID_ARG_TYPE('listener', 'Function', listener);
- }
+ checkListener(listener);
+
 this.on(type, _onceWrap(this, type, listener));
 return this;
 };
 
 EventEmitter.prototype.prependOnceListener =
 function prependOnceListener(type, listener){
- if (typeof listener !== 'function'){
- const errors = lazyErrors();
- throw new errors.ERR_INVALID_ARG_TYPE('listener', 'Function', listener);
- }
+ checkListener(listener);
+
 this.prependListener(type, _onceWrap(this, type, listener));
 return this;
 };
@@ -306,10 +306,7 @@ EventEmitter.prototype.removeListener =
 function removeListener(type, listener){
 var list, events, position, i, originalListener;
 
- if (typeof listener !== 'function'){
- const errors = lazyErrors();
- throw new errors.ERR_INVALID_ARG_TYPE('listener', 'Function', listener);
- }
+ checkListener(listener);
 
 events = this._events;
 if (events === undefined)

-Original file line number
+Diff line change
 returnerrors;
+}
 +functioncheckListener(listener){
 +if(typeoflistener!=='function'){
 +consterrors=lazyErrors();
 +thrownewerrors.ERR_INVALID_ARG_TYPE('listener','Function',listener);
 +}
 +}
++
 Object.defineProperty(EventEmitter,'defaultMaxListeners',{
 enumerable: true,
 get: function(){
 varevents;
 varexisting;
 -if(typeoflistener!=='function'){
 -consterrors=lazyErrors();
 -thrownewerrors.ERR_INVALID_ARG_TYPE('listener','Function',listener);
 -}
 +checkListener(listener);
 events=target._events;
 if(events===undefined){
+}
 EventEmitter.prototype.once=functiononce(type,listener){
 -if(typeoflistener!=='function'){
 -consterrors=lazyErrors();
 -thrownewerrors.ERR_INVALID_ARG_TYPE('listener','Function',listener);
 -}
 +checkListener(listener);
++
 this.on(type,_onceWrap(this,type,listener));
 returnthis;
 };
 EventEmitter.prototype.prependOnceListener=
 functionprependOnceListener(type,listener){
 -if(typeoflistener!=='function'){
 -consterrors=lazyErrors();
 -thrownewerrors.ERR_INVALID_ARG_TYPE('listener','Function',listener);
 -}
 +checkListener(listener);
++
 this.prependListener(type,_onceWrap(this,type,listener));
 returnthis;
 };
 functionremoveListener(type,listener){
 varlist,events,position,i,originalListener;
 -if(typeoflistener!=='function'){
 -consterrors=lazyErrors();
 -thrownewerrors.ERR_INVALID_ARG_TYPE('listener','Function',listener);
 -}
 +checkListener(listener);
 events=this._events;
 if(events===undefined)