> On Sep 28, 2014, at 8:01 AM, Marius Gundersen <[email protected]> wrote: > > It would be helpful if the stack trace was machine readable, not just human > readable. As Erik said
+1 > > [...] we might ass well stop using a string to represent this structured data. > > The stacktrace should probably be an array of objects with the properties > `filename`, `function`, `line` and `column`. It would then be simple to > format this stacktrace as a string and make it look exactly like it does in > browsers today. With a machine readable stack trace it would be easier to > build editor sandboxes (jsbin, codepen.io <http://codepen.io/>, etc) where > errors inside the sandbox could be caught by the editor and shown to the user. > > Another feature of the stacktrace as an array is that a library could > manipulate the stack trace after it has been thrown, to hide the internals of > the library. This is similar to the black box feature in the Firefox > devtools. For example, a divide function which takes two integers could throw > an error when the second parameter is 0 (can't divide by zero). This would > result in the library internals ending up in the stack trace: > > ```js > function calculate(x, y){ > return myIntegerMathLibrary.divide(2, x)*y; > } > > calculate(0, 5) > /* > Exception: Second parameter is '0'; can't divide by zero > divide@myIntegerMathLibrary/divide.js:15:15 <= this is library code,it's not > helpful to the developer > calculate@myApplication:2:3 <= this tells the developer where the problem is > in their code > @myApplication:4:1 > */ > ``` > > If the library was allowed to manipulate the stack of the Error object before > throwing it, it could remove the top n lines that are internal to it, which > would help the developer locate the issue in their code. > > Since all modern browsers implement a non-standard stack trace it is possible > to find out what file you are in and what line you are on by throwing and > catching an exception and analyzing the stack string. If stack traces are > added to the standard, then maybe a reflection API that can tell what file > and line the code is on should be added as well. The module meta object will > most likely get a filename property, but line number/character number is not > yet available. > > Marius Gundersen > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
