repr.js

Sick of 99% of objects in your runtime being represented as [object Object]? I sure am. repr takes a leaf out of python's book, and gives some identity to your objects so you can tell what they are without jumping through hoops.

It adds two global methods:

• str(obj): print out a summary of obj
• repr(obj): print out a more detailed representation of obj (similar to inspect() in ruby, and obviously repr in python)

It also overrides Object.toString() to use str, because that way you'll suddenly get useful information throughout your app in code that you don't necessarily control - in error messages, exceptions, and whenever you concatenate strings together. Note that you should never rely on the format of this (or any) toString() behaviour unless you specifically override it - the default implementation of Object.toString() is purely for informational purposes.

Here's some examples:

function Foo() {
  this.x = "123";
}
var f = new Foo();
f.complex = {a: 123, b:456};
f.fun = function() { };


>>> str(null)
(null)
>>> str(undefined)
(undefined)
>>> str([1,2,3])
[1, 2, 3]
>>> str({})
{}
>>> repr({a:"b"})
{"a": "b"}
>>> str(f)
<# object Foo>
>>> repr(f)
<# Foo; x: 123, complex: {"a":123,"b":456}, fun: (anonymous function)>
>>> repr(Foo)
function Foo() {
  this.x = "123";
}
>>> str(Foo)
(function Foo)
>>> str([1,f,3])
[1, <# object Foo>, 3]
>>> repr([1,f,3])
[1, <# Foo; x: 123, complex: {"a":123,"b":456}, fun: (anonymous function)>, 3]
>>> repr("foo\" bar")
"foo\" bar"

The code ends up dealing with a lot of edge cases, because javascript's type system is somewhat laden with traps. So please report any issues you find, and I'll endeavor to fix them as they come up.

Usage:

In the browser, you need only load it with a <script> tag. In node.js, you must require() it. You can either use the returned module's repr and str functions individually, or call the module's install method passing in the global object in order to install these same functions into the global scope.