speed: committing a failing experiment of concat vs slice

speed/slice.vs.concat.html

@@ -0,0 +1,46 @@
+<script type="text/javascript">
+(function(){
+	// Conclusion: slice is a little faster except on Chrome
+	// clone() is slower on FF & IE but takes 50% on Safari & Chrome
+
+	var SIZE = 1e4,
+		LOOPS = 500;
+	
+	var arr = new Array(SIZE);
+	for ( var i=arr.length-1; i >= 0; --i )
+		arr[i] = 0;
+
+	var t = new Date;
+	for ( i=0; i < LOOPS; i++ )
+		arr.slice(0);
+	var tslice = new Date - t;
+	
+	t = new Date;
+	for ( i=0; i < LOOPS; i++ )
+		arr.concat();
+	var tconcat = new Date - t;
+	
+	// clone() is just to see how fast built-ins are
+	t = new Date;
+	for ( i=0; i < LOOPS; i++ )
+		clone(arr);
+	var tclone = new Date - t;
+	
+	alert([
+		'slice:'+tslice,
+		'concat:'+tconcat,
+		'clone:'+tclone
+	].join('\n'));
+	
+	
+	function clone(arr){
+		var i = arr.length,
+			copy = new Array(i);
+			
+		while (i--)
+			copy[i] = arr[i];
+			
+		return copy;
+	}
+})();
+</script>