nv / jsdump

Fork of jsDump by Ariel Flesler

jsDump

jsDump.parse(object) returns a string containing a human-readable representation of object.

jsDump is like Mozilla’s toSource(), but it works in all modern browsers.

jsDump was originally developed by Ariel Flesler. This fork based on version 1.0.0.

Similar Stuff

• JSON.stringify(). Doesn’t serialize functions and DOM nodes.
• inspect() from Node.js sys module
• repr() from Narwhal’s util module
• console._source_of() from Console.js

NPM

npm install jsDump

Usage:

var jsDump = require("jsDump");
jsDump.parse({foo: 'bar', length: 0});

Tests

In the browser:

1. git submodule update --init
2. open tests/index.html

Or from command line:

$ narwhal tests/*_test.js

Contribution

Use jQuery coding style. Basically, use tabs instead of spaces.

jsdump's Issues

JSON with a key of "length" causes a problem

JSON requires quotes around keys so reserved words don't cause a problem. But I suspect there's an issue with jsDump's parsing because it returns "[ ]" for the following valid JSON:

{
"width": 0,
"length": 0
}

Change it slightly though:

{
"width": 0,
"length_": 0
}

and it parses and formats it just fine. My guess is that other reserved words might cause similar problems though I haven't tested that to make sure.

The “arguments” object detection causes problems

Inside the typeOf function, the arguments object is detected using the callee property:

if ( 'callee' in obj )
  // Opera: Object.prototype.toString.call(arguments) == 'Object' :(

This creates a problem in at least two situations:

1. When dealing with regular objects containing the callee property, such as AST nodes resulting from parsing JavaScript by a parser conforming to Mozilla SpiderMonkey Parser API (or its successor, The ESTree Spec).
2. In JavaScript strict mode, which defines (5.1, 6.0) the callee getter to throw an exception. This can be demonstrated e.g. using this code in recent Chrome: (function() { "use strict"; arguments.callee; })();).

The first case frequently bites users of the online editor at PEG.js website.

Since Object.prorotype.toString called on an arguments object returns [object Arguments] on recent versions of all common browsers (including Opera mentioned in a comment in jsDump code), I think it would be better to rewrite the detection to use it to detect arguments instead of the callee property.