return the line number in JavaScript [duplicate]

Question

I want to return the line number in my code, for example I want when I write console.log('SomeCode'); in the line 33 to return 33.

How can I do that in JavaScript?

I googled about it and I found this code :

try{ throw new Error('Buck stops here') }catch(e){ console.log( e.line) }

But I don't want to use any try catch in my code.

Finding it from the stack trace is the only way. Try-catch is a valid construct, why don't you want to use it? — Emissary
– Emissary, Commented Feb 8, 2014 at 14:39
@Emissary I think the intent was to avoid the try / catch in his example, which in that case the try / catch is redundant since you could just assign the Error object to a variable instead of throwing and catching. — Sukima
– Sukima, Commented Feb 8, 2014 at 14:45

Sukima · Accepted Answer · 2014-02-08 14:41:56Z

4

Skip the try / catch and just use the Error object:

var x = new Error("I want the line number"); console.log(x.lineNumber);

More information is available at the MDN Docs

Also note that proprties like lineNumebr are implemented in specific interpreters and is not universal across all browsers.

answered Feb 8, 2014 at 14:41

Sukima

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2 Comments

Renaud is Not Bill Gates Over a year ago

When I tried this I got Indefined in console, I think the lineNumber property is valide on Firefox and Opera and not Google Chrome, because I'm using Google Chrome

Sukima Over a year ago

if it is not available in your environment you might have to do your own regex parsing of x.stack to find it. There might be some snippets out there that do this.

vitkon · Accepted Answer · 2014-02-08 14:40:34Z

-1

you need to catch all unhandled exceptions in your code. By doing this you won't need to put "try-catch" construction in.

window.onerror = function myErrorHandler(errorMsg, url, lineNumber) { console.log("Error occured: " + errorMsg + " on line " + lineNumber);//or any message return false; }

MDN Reference

answered Feb 8, 2014 at 14:40

vitkon

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4 Comments

Sukima Over a year ago

This feels like a code smell. It could easily mask legit runtime errors you might expect to throw.

vitkon Over a year ago

Agreed. You can throw an error in this block if you want. Depends what you are trying to achieve.

Brandon Over a year ago

While this technique may be useful in some circunstances, This is awful advice for the question asked.

vitkon Over a year ago

I re-read the question and now I see that I didn't get it right ;)

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