events: onceWrapper apply directly with arguments

apapirovski · apapirovski · commit fe13e0077f59 · 2017-10-21T09:29:09.000-04:00
Due to changes in V8 in 6.0 & 6.1, it's no longer necessary to copy arguments to avoid deopt. Just call .apply with arguments. Retains fast cases for 0-3 arguments. events/ee-once-4-args.js n=20000000 11.58 % *** 1.310379e-05 PR-URL: nodejs#16212 Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Refael Ackermann <refack@gmail.com>
diff --git a/lib/events.js b/lib/events.js
@@ -328,10 +328,7 @@ function onceWrapper() {
         return this.listener.call(this.target, arguments[0], arguments[1],
                                   arguments[2]);
       default:
-        const args = new Array(arguments.length);
-        for (var i = 0; i < args.length; ++i)
-          args[i] = arguments[i];
-        this.listener.apply(this.target, args);
+        this.listener.apply(this.target, arguments);
     }
   }
 }

Original file line number	Diff line number	Diff line change
`@@ -328,10 +328,7 @@ function onceWrapper() {`
`328`	`328`	`return this.listener.call(this.target, arguments[0], arguments[1],`
`329`	`329`	`arguments[2]);`
`330`	`330`	`default:`
`331`		`- const args = new Array(arguments.length);`
`332`		`- for (var i = 0; i < args.length; ++i)`
`333`		`- args[i] = arguments[i];`
`334`		`- this.listener.apply(this.target, args);`
	`331`	`+ this.listener.apply(this.target, arguments);`
`335`	`332`	`}`
`336`	`333`	`}`
`337`	`334`	`}`