util: faster arrayToHash

The `util.format()` is used frequently, make the method faster
is better.

R-URL: nodejs#3964
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Brian White <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Makefile

@@ -493,6 +493,9 @@ bench-url: all
 bench-events: all
  @$(NODE) benchmark/common.js events
 
+bench-util: all
+ @$(NODE) benchmark/common.js util
+
 bench-all: bench bench-misc bench-array bench-buffer bench-url bench-events
 
 bench: bench-net bench-http bench-fs bench-tls

benchmark/util/inspect.js

@@ -0,0 +1,15 @@
+var util = require('util');
+
+var common = require('../common.js');
+
+var bench = common.createBenchmark(main, {n: [5e6]});
+
+function main(conf) {
+ var n = conf.n | 0;
+
+ bench.start();
+ for (var i = 0; i < n; i += 1) {
+ var r = util.inspect({a: 'a', b: 'b', c: 'c', d: 'd'});
+ }
+ bench.end(n);
+}

lib/util.js

@@ -163,9 +163,10 @@ function stylizeNoColor(str, styleType) {
 function arrayToHash(array) {
  var hash = Object.create(null);
 
- array.forEach(function(val) {
+ for (var i = 0; i < array.length; i++) {
+ var val = array[i];
  hash[val] = true;
- });
+ }
 
  return hash;
 }