Question

I am trying to define a class, but when I reference it in my code I get an error

Error: declare custom.place: mixin #0 is not a callable constructor

define(['dojo', 'dijit/dijit', "dojo/_base/declare", "dijit/place"],
   function(dojo, dijit, declare, place) {

     return declare("custom.place", [place], {
       newMethod: function() { }
   });
 })

This will not work. But the following code, works fine!

define(['dojo', 'dijit/dijit', "dojo/_base/declare", "dijit/MenuItem"],
   function(dojo, dijit, declare, MenuItem) {

   return declare("custom.item", [MenuItem], {
       newMethod: function() { }
   });
})

Any help is appreciated. Thanks.

Answer 1

Dojo classes can only extend other Dojo classes. dojo/place is not a Dojo class; it is merely an object with some function properties.

require(["dijit/place", "dijit/MenuItem"], function(place, MenuItem) {
  console.log(typeof place);
  console.log(typeof MenuItem);
});

The above code gives the console output:

LOG: object 
LOG: function 

If you want an object with place’s utility functions and some extra ones, you could create your own version like this:

define(["dojo/_base/lang", "dijit/place"], function(lang, place) {
  var newMethods = {
    foo : function () {}
  };

  return lang.mixin(newMethods, place);
});

If you wanted to mixin place’s functionality to a Dojo class you could do it using safeMixin but I’m not sure why you would want to.