Try/Catch Cost In a Loop

JavaScript performance comparison

Test case created by Jackson Gabbard


How much does a try catch cost?

Preparation code

Benchmark.prototype.setup = function() {
    var obj = { a : 1, b : 2, c : 3, d : 4, e : 5 };

Test runner

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Testing in unknown unknown
Test Ops/sec
Vanilla iteration
var blah = '';
for (var prop in obj) {
  blah += obj[prop];
Iteration with internal try/catch
var blah = '';
for (var prop in obj) {
  try {
    blah += obj[prop];
  } catch (e) {
    console.log(' ');

Compare results of other browsers


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1 comment

Neil Whitaker commented :

I was curious to see how a try-catch outside the loop would compare, so I added a third test. In my version of Chrome, it was surprisingly close to the try-catch in the loop. It may be the performance difference is due to compiler optimizations that are lost in a try-catch scenario.

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