[traits.js] Confused

[Nathan]

I'm receiving some confusing behavior.

Here is an example:

var obj = Trait.create({ hello: "world" }, Trait({ toString:
function() { return this.hello; } }));
obj.toString(); // -> "world"

var obj = Trait.create({ hello: "world" }, Trait({
hello: Trait.required,
toString: function() { return this.hello; }
}));
obj.toString(); // -> this.hello is undefined

I don't understand why marking it as required makes it undefined when
I provide hello via the prototype in the same way.

[Tom Van Cutsem]

Hi Nathan,

You just discovered the first bug in traits.js v0.1 ;-)

The bug is fixed in the head release:

http://code.google.com/p/es-lab/source/browse/trunk/src/traits/traits.js

With the fix, your example will return 'world' for both cases, as it should.

Cheers,

Tom

2010/5/8 Nathan <nrs...@gmail.com>

[Nathan Stott]

Yay, first bug ^^

Thanks for the fix!

[Nathan Stott]

Tom,

I am using this Trait as a CommonJS module.  It would be excellent if you added support for this by adding at the end of the file

if (exports) {

    exports.Trait = Trait;

[Tom Van Cutsem]

Done. I did use a slightly different feature-test as undefined free variables result in exceptions on some JS engines:

if (typeof exports !== "undefined") { // CommonJS module support

  exports.Trait = Trait;

}

2010/5/10 Nathan Stott <nrs...@gmail.com>

[Nathan Stott]

Perfect, thanks

[Mark S. Miller]

On Mon, May 10, 2010 at 7:32 AM, Tom Van Cutsem <tvcu...@gmail.com> wrote:

Done. I did use a slightly different feature-test as undefined free variables result in exceptions on some JS engines:

Hopefully all. That exception is required by the spec. Your test is the correct fix.

Nathan, thanks for the report!

--
    Cheers,
    --MarkM

[Nathan Stott]

No problem, I'm enjoying using traits