Fastest way to test two strings for exact match in JavaScript

Question

I want to compare two strings in JavaScript to test if they are exactly the same. Which would be the best (fastest) way to do this?

Right now, I'm considering either

if(string1.localeCompare(string2) == 0) {}

or simply

if(string1 == string2)

Is there a better way do to this?

score 31 · Accepted Answer · edited May 23 '17 at 12:32

31

I would probably use strict equality if you want to check they are exactly the same, ie they're the same type too, just in case.

if (string1 === string2)

edited May 23 '17 at 12:32

Community

answered Sep 03 '13 at 09:10

Andy

Is that the fastest solution, as requested? If so, can you add supporting evidence? – Lee Goddard Jan 23 '23 at 08:53
@LeeGoddard you're asking about an answer I wrote a decade ago. Run the tests yourself if you want. – Andy Jan 23 '23 at 09:00

score 6 · Answer 2 · answered Sep 03 '13 at 09:18

6

Check this fiddle* and figure out yourself which one is faster.

*In case the link dies in the future: == > === > String.localeCompare (tested on Chrome).

answered Sep 03 '13 at 09:18

Savas Vedova

2

But, as stated in an answer and comment, `==` does not even meet the requirement of checking for an exact match, at least not in the uninformed case. – Ingo Bürk Sep 03 '13 at 09:33
@IngoBürk Yeah I know. But still for cases when you do not need strict comparison == is faster. That's only an information, I showed the speeds and choosing the method is only up to you :) – Savas Vedova Sep 03 '13 at 09:52
Just what I needed. @IngoBürk, while you're *strictly* correct, I think the meaning of exact is highly contextual. – seebiscuit Jun 29 '15 at 18:03

score 2 · Answer 3 · answered Sep 03 '13 at 09:04

2

I'm not sure there is any room to optimize if(string1 == string2). That is the best approach.

answered Sep 03 '13 at 09:04

Kevin Bowersox

4

Unless you already know that they are strings, using `===` is essential. – Ingo Bürk Sep 03 '13 at 09:09

score 1 · Answer 4 · answered Sep 03 '13 at 09:18

1

if (typeof string1=="string" && typeof string2=="string" && string1 === string2)

no escape method :)

answered Sep 03 '13 at 09:18

kangoroo

1

I like the thought, but you can omit the second `typeof`. – Ingo Bürk Sep 03 '13 at 09:37

4 Answers4