benchmark.js

if (typeof print === 'undefined') print = function(str) { console.log(str); };

function bench() {
  function big_switch(x) {
    switch ('__' + x + '__') {
      default: return 0;
      case "__1__": return 1;
      case "__2__": return 2;
      case "__3__": return 3;
      case "__4__": return 4;
      case "__5__": return 5;
      case "__6__": return 6;
      case "__7__": return 7;
      case "__8__": return 8;
      case "__9__": return 9;
      case "__10__": return 10;
      case "__11__": return 11;
      case "__12__": return 12;
      case "__13__": return 13;
      case "__14__": return 14;
      case "__15__": return 15;
      case "__16__": return 16;
      case "__17__": return 17;
      case "__18__": return 18;
      case "__19__": return 19;
      case "__20__": return 20;
    }
  }

  function show(offset) {
    print('starting the show');
    var start = +new Date;
    for (var i = 1; i <= count; i++) {
      for (var k = 0; k < different; k++) {
        big_switch(k + offset);
      }
    }
    var end = +new Date;
    print('show ended: ' + (end - start) + 'ms');
  }
  var different = 8,
      count = (40000000 / different) | 0;

  show(1);
  show(10);
  show(3);
  show(9);

  for (var k = 1; k <= 20; k++) {
    print(big_switch(k));
  }
}
bench();