dijit.Declaration and its mixins

I love the dijit.Declaration widget introduced into the dojo toolkit around version 0.9+. It lets you declare a new widget class inline in your html - which can be very useful, especially when you want the widget templateString to be dynamic output from the server.

Just a little tip - I had been getting a

m._findMixin is not a function
error when instantiating widgets from my Declaration. If you’ve ever tried to step through widget instantiation you have an idea how sigh-worthy this particular error was. After a little debugging and poking through Declaration.js I noticed that the mixins property was typed as an array. When using dojo.declare directly, the parent class is the 2nd argument. And if you need mixins (like dijit._Templated) you make that 2nd argument an array and list them out in order as its content. So, it can be either a string or an array and dojo.declare will do the right thing. It turns out that with dijit.Declaration, the mixins property must be an array, even if you only have one value to put in there:


Which put me back in action, and I hope steers you around this particular hole in the road.