Long stack traces

[OliverJAsh]

I would really like to see long (async) stack traces supported in Traceur. This is currently possible with modules such as longjohn.

[OliverJAsh]

Having this would really help debugging with Traceur. When doing anything async, long stack traces are a must.

Can anyone talk me through where this belongs (in Traceur or in tooling) and how it might be implemented? Willing to look into this myself.

[arv]

Since Chrome supports this natively do we really need to do anything?

[OliverJAsh]

@arv I'm using Traceur via Node.js, so that doesn't help me much, unless I misunderstand?

[johnjbarton]

What is the command you use when you are "using Traceur via Node.js"? Seems like that command just needs the longjohn require.

[OliverJAsh]

// traceur-runner.js
'use strict';

var traceur = require('traceur');
require('traceur-source-maps').install(traceur);
var path = require('path');

// var longjohn = require('longjohn');
// longjohn.async_trace_limit = -1;

var whitelist = [];

traceur.require.makeDefault(function (modulePath) {
    var isDependency = modulePath.indexOf('node_modules') !== -1;
    var isWhitelistedPackage = whitelist.some(function (whitelistItem) {
        return modulePath.indexOf(whitelistItem) !== -1;
    });

    return ! isDependency || isWhitelistedPackage;
});


require(path.resolve(process.cwd(), process.argv[2]));

And then:

node traceur-runner.js main.js

I apply the traceur-source-maps package which maps error stack traces back to source (this is not done by default, see #1433).

If I then try to apply longjohn after this (commented out), it undoes the work done by traceur-source-maps, leaving me with long stack traces but mapped to the compiled ES5 code, not the source ES6.

My goal is to have source map resolved and long stack traces.

[johnjbarton]

Take a look at src/node/System.js and pass {sourceMaps: true} as the options argument to makeDefault.

[OliverJAsh]

Was #1433 was supposedly fixed by #1475?

I just tested it here:

https://gist.github.com/OliverJAsh/0a9fb23dc3ea9bc7914c

When I run the Node script through Traceur, my error call stack is still incorrect:

/Users/Oliver/Development/tmp/traceur-longjohn/main.js:10
    throw new Error('foo');
          ^
Error: foo
    at foo [as _onTimeout] (/Users/Oliver/Development/tmp/traceur-longjohn/main.js:10:11)
    at Timer.listOnTimeout [as ontimeout] (timers.js:112:15)

The sourceMaps option seems to make no difference here.