stack-displayName

Show custom function names in error stack traces

Description

Safari, Chromium and Firefox implemented ability to set custom string as function name via non-standard property displayName.

You can see those custom names in debugger stack and so easier track source of error in long traces of anonymous functions.

Compare stack traces of error before and after using this ability in jBinary:

Before vs After

However, since this property was implemented on level of developer tools and not JS core itself, in Node.js for analogical code you still get:

before

This drop-in library stringifies error stack traces in V8 both in browser and Node.js that simulates core formatting but respects displayName property, so when error occurs, you get stylish stack trace:

after

Installation and usage

In Node.js

Simply install with npm as:

npm install stack-displayname

and require it:

require('stack-displayname');

In Browser

This script would work only in Chromium, where DevTools already respect displayName, but in the case you want to have custom function names in err.stack property of any Error instances (which is not natively supported), that's possible via simple script tag:

<script src="stack-displayname/displayName.js"></script>

Other browsers will just ignore instructions and show stack traces as usual.

Usage

var f = function () {
  throw new Error();
};
 
f.displayName = "super puper function";
 
f(); // enjoy descriptive stack trace!

License

Copyright 2006-2011, the V8 project authors. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright
  notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the following
  disclaimer in the documentation and/or other materials provided
  with the distribution.
* Neither the name of Google Inc. nor the names of its
  contributors may be used to endorse or promote products derived
  from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.