Can't get lastIndexOf to work

Question

I have this code

var url = 'http://sitename.com/category/diving/',
    catName = url.substr(url.lastIndexOf('/') + 1);

And when I try to run alert(catName) it returns empty string. What am I doing wrong?

Try doing some debugging. For example, do `url.lastIndexOf('/')` and you'll see it returns `35` which is the correct index of the last `/`. From there you can go on to solve the other part of your problem. — David Sherret, Mar 15 '15 at 16:07

score 2 · Accepted Answer · answered Mar 15 '15 at 16:08

2

You need the category name but you have to remove first the last /:

var url = 'http://sitename.com/category/diving/';
url = url.substr(0, url.length - 1);
catName = url.substr(url.lastIndexOf('/') + 1);

Result:

"diving"

answered Mar 15 '15 at 16:08

JuniorCompressor

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score 1 · Answer 2 · answered Mar 15 '15 at 16:04

1

because you add +1 to the index, so you get undefined string. remove the +1 in the lastIndexOf

answered Mar 15 '15 at 16:04

David Haim

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Then it returns `/`. When I add `-1`, it returns `g/`. – Tomek Buszewski Mar 15 '15 at 16:05
@TomekBuszewski I think you're misunderstanding substr then. – David Sherret Mar 15 '15 at 16:06
why not use split('/')[length-1] – David Haim Mar 15 '15 at 16:07
I used it before, but it was slower than this. Perhaps I shoud go back to using it then. – Tomek Buszewski Mar 15 '15 at 16:08
1

micro optimization is the source of all evil , especially in a language like JS which speed is not a main feature inside . – David Haim Mar 15 '15 at 16:09
Well, when you have a lot of urls, some ajax etc., you want every ms you can get ;-) – Tomek Buszewski Mar 15 '15 at 16:10

score 0 · Answer 3 · edited May 23 '17 at 10:24

0

You can use..parseUri

var url = 'http://sitename.com/category/diving/';
url = url.substr(0, url.length - 1);
var filename1 = parseUri(url ).file;--way1
var filename2 = url.match(/.*\/(.*)$/)[1];

Result="diving";

Ways to achieve this

edited May 23 '17 at 10:24

Community

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answered Mar 15 '15 at 16:21

A_Sk

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Where do you define `parseUri`? – David Sherret Mar 15 '15 at 16:21
i just add @DavidSherret – A_Sk Mar 15 '15 at 16:27

Can't get lastIndexOf to work

3 Answers3