Javascript regex match the last occurance

Question

Question:
Using regular expressions in javascript, if I have a string that contains zero or more newlines or carriage returns, what is the best way to tell how many characters are after the last newline or carriage return?

Attempts:
I've tried various regular expressions, but with no luck. Say I have the string:

"_\nHELLO\nWORLD\nSALUTATIONS"
In normal output, it looks like this:
_ HELLO WORLD SALUTATIONS

Shouldn't /^(\r|\n){1}/g find a string globally g, with only one occurance {1} of a return or newline (\r|\n), or, in this case, "SALUTATIONS"? Instead no match is found.

adeneo · Accepted Answer · 2014-06-25 18:46:33Z

4

How about not using a regex

string.split(/\r|\n/).pop().length;

That splits the string on newlines, pops off the last one and get's the number of characters with length

edited Jun 25, 2014 at 18:46

answered Jun 25, 2014 at 18:20

adeneo

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5 Comments

Aaron Thomas Over a year ago

does "pop" pull the last element in the array created by the split?

Bergi Over a year ago

You should split on /\r|\n/, though

adeneo Over a year ago

@Bergi - does any browser really use \r now? I know old IE used to return \r\n, and not just \r, but I didn't think this was an issue anymore ?

Bergi Over a year ago

It might not be necessary, yes, but we don't know where the string came from and it's what the OP asked for.

adeneo Over a year ago

@Bergi - sure, changed it, doesn't really matter to me?

Bergi · Accepted Answer · 2014-06-25 18:22:24Z

1

No, your regex will find CRs/NLs only at the very beginning of the string, because you have an ^ anchor right there.

To find the last one, you rather will want to anchor your expression at the end of the string:

/[\r\n]([^\r\n]*)$/

By matching that, you will get all the characters after the last linebreak in the first capturing group.

answered Jun 25, 2014 at 18:22

Bergi

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Comments

Oriol · Accepted Answer · 2014-06-25 18:41:48Z

0

Try this:

string.length - string.lastIndexOf('\n') - 1

Or if you really need to also check \r,

string.length - string.search(/[\n\r].*?$/) - 1

edited Jun 25, 2014 at 18:41

answered Jun 25, 2014 at 18:22

Oriol

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1 Comment

Bergi Over a year ago

Should be Math.max(string.lastIndexOf('\n'), string.lastIndexOf('\r'))

bukart · Accepted Answer · 2014-06-25 19:27:51Z

0

A short and simple way would be this

console.log(text.match(/.*$/)[0].length);

$ marks the end of the string and by default . does not match line breaks, so the matched result is exactly the last line.

answered Jun 25, 2014 at 19:27

bukart

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