__line_number__ and __filename__

[Bob Myers]

What does line number, or filename for that matter, mean when a file has
gone through one or more transpilation and/or minification passes?
Is the notion that the first processor that touches the file would
substitute those values?

Bob


On Fri, Aug 24, 2018 at 11:34 PM Claude Pache <claude.pache at gmail.com>
wrote:

>
>
> Le 24 août 2018 à 05:55, J Decker <d3ck0r at gmail.com> a écrit :
>
> On Thu, Aug 23, 2018 at 5:26 PM Aaron Gray <aaronngray.lists at gmail.com>
> wrote:
>
>> I am debugging existing code that I have modularized, and am class'izing
>> that has unittests and it just would have been very useful to have this
>> facility.
>>
> In a  browser, console.log is usually associated with the file and line
> number anyway; which includes using devtools with node.... but it would be
> handy for logging.  with V8 there is console.trace; which spits out the
> stack trace too... before I discovered that I did a logging function
> like...
>
> (from
> https://stackoverflow.com/questions/591857/how-can-i-get-a-javascript-stack-trace-when-i-throw-an-exception
> )
> function stackTrace() { var err = new Error(); return err.stack; }  //
> parse stack to get frame-1 online
>
> // or maybe just frame-1...
> function stackTrace() { var err = new Error(); return err.stack.split(
> "\n" )[1]; }
>
> ---
> function stacktrace() {
>   function st2(f) {
>     return !f ? [] :
>         st2(f.caller).concat([f.toString().split('(')[0].substring(9) +
> '(' + f.arguments.join(',') + ')']);
>   }
>   return st2(arguments.callee.caller);
> }
>
>  EDIT 2 (2017) :
>
> In all modern browsers you can simply call: console.trace(); (MDN
> Reference)
> ---
>
> Although I do still miss just being able to get __FILE__ and __LINE__
>
>
>
> See also:
>
> https://github.com/tc39/proposal-error-stacks
>
> If/when that proposal is implemented, you'll have a simple way to get a
> *structured* representation of the trace:
>
> ```js
> System.getTrace(new Error)
> ```
>
> from which you can much more easily extract line number, filename, etc.
>
> —Claude
>
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