Ajaxian

Wednesday, January 11th, 2006

Dojo Tips: Cookies, and a nice Curry

Category: Articles, Dojo, JavaScript, Toolkit

Dojo continues to have nice wrappers that make it easy for you to do real things.

A couple of topics came up this week such as cookies, and a new curry mechanism:

Dojo Cookies

Dojo has helper cookie methods wrapped up in the dojo.io.cookie package (src).

Example usage:


dojo.io.cookie.set(”mycookie”, “my value”, 30); // set ‘mycookie’ to ‘my value’, expires in 30 days
alert(dojo.io.cookie.get(”mycookie”)); // should alert “my value”


Cache Busting

If you use the dojo.require(..) mechanism, you may need to push through the browser cache that helps out GET requests (and hurts in this case).

Simply use the djConfig.cacheBust value:


djConfig.cacheBust = new Date().valueOf().toString(); // random value. bad in all but dev
djConfig.cacheBust = “version-0.2.1″; // be explicit
dojo.require(”dojo.string”); // will get string.js?version-0.2.1


Can I have a curry with those cookies?

Alex Russell added a curry method:


var curried = dojo.lang.curry(namespace, funcName /* args … */);


The returned function executes in the context of namespace with whatever arguments are passed past that filled in as the expected arguments. So if the function defined is:


function foo(bar, baz, xyzzy, thud){ … }


we can “fill in” some arguments using curry(), like this:

var foo2 = dojo.lang.curry(null, "foo", "bar value", "baz value");

And now foo2 is a function which expects 2 arguments instead of 4.
Calling it with fewer than 2 arguments will return a similarly “filled in” function that expects the remaining number of methods:


var foo3 = foo2(”xyzzy value”);
// foo3 now expects 1 value


When foo3 is now called with one or more arguments, it will “unroll” the chain and call foo() with the accumulated arguments.

Posted by Dion Almaer at 1:10 am