Testing http://github.com/NV/run-this-gist

flatten_2_dimension_array_bench.js

var TOTAL = 3000;
 
// Prepare test data
var b = [];
for (var i=0; i<TOTAL; ++i) {
  b[i] = [i];
}
 
 
(function(){
  var a = [];
  var start = new Date;
  for (var i=0; i<TOTAL; ++i) {
    a = a.concat(b[i]);
  }
  var end = new Date;
  print("      concat: " + (end - start) + "ms");
})();
 
(function(){
  var a = [];
  var start = new Date;
  for (var i=0; i<TOTAL; ++i) {
    a.push.apply(a, b[i]);
  }
  var end = new Date;
  print("  push.apply: " + (end - start) + "ms");
})();
 
(function(){
  var start = new Date;
  var a = [];
  for (var i=0; i<TOTAL; ++i) {
    for (var j=0; j<b[i].length; ++j) {
        a[i] = b[i][j]
    }
  }
  var end = new Date;
  print( "  inner loop: " + (end - start) + "ms" );
})();
 
(function(){
  var start = new Date;
  var a = Array.prototype.concat.apply([], b);
  var end = new Date;
  print("concat.apply: " + (end - start) + "ms");
})();