Performance of if-else, switch or map based conditioning

Question

I was wondering about the performances of the following implementations of conditional structs in javascript.

Method 1:

 if(id===\         


        

Answer 1

You can always do a jsPerf test yourself. However, in general a lookup table is the fastest way to access data. That would be (3) in your snippets. Also, switch/case is almost always faster than if-else. So the order for your example would be

(3) -> (4) -> (2) -> (1)

Answer 2

Just thought I'd add this as a possible consideration. I came across this doing research on this very question... http://davidbcalhoun.com/2010/is-hash-faster-than-switch-in-javascript

It takes different engines and browsers into account.

Answer 3

According to this JSBen.ch test, the switch setup is the fastest out of the provided methods (Firefox 8.0 and Chromium 15).

Methods 3 and 4 are slightly less fast, but it's hardly noticeable. Clearly, the if-elseif method is significantly slower (FireFox 8.0).

The same test in Chromium 15 does not show significant differences in performance between these methods. In fact, the if-elseif method seems to be the fastest method in Chrome.

Update

I have run the test cases again, with 10 additional entries. The hrefmap (methods 3 and 4) show a better performance.

If you want to implement the compare method in a function, method 3 would definitely win: Store the map in a variable, and refer to this variable at a later point, instead of reconstructing it.