Optimize compiler opcode call

lib/handlebars/compiler/compiler.js

@@ -1,6 +1,8 @@
 import Exception from "../exception";
 import {isArray} from "../utils";
 
+var slice = [].slice;
+
 export function Compiler() {}
 
 // the foundHelper register will disambiguate helper lookup from finding a
@@ -292,7 +294,7 @@ Compiler.prototype = {
 
   // HELPERS
   opcode: function(name) {
-    this.opcodes.push({ opcode: name, args: [].slice.call(arguments, 1) });
+    this.opcodes.push({ opcode: name, args: slice.call(arguments, 1) });
   },
 
   addDepth: function(depth) {