I am trying to use an around aspect for the expand function of a GridX's tree.
The simplified code goes like:
var myGrid = ...; // features a tree
var myConditional = ...; // some boolean
dojo.aspect.around(myGrid.tree, "expand", function(original) {
return function(id, skip) {
// TODO check the conditional and decide whether
// to return the deferred function as is, or
// return a function that does nothing but log into the console
var deferred = original(id, skip);
return deferred;
};
});
Unfortunately, the invocation of dojo aspect as is (i.e. without any check for my conditional, etc.) is problematic.
Once the expando is clicked, an error is thrown in the console:
Uncaught TypeError: t.isExpanded is not a function
... pointing at the body of the GridX tree module's expand original function:
var d = new Deferred(), t = this;
if(!t.isExpanded(id) && t.canExpand(id)){ // here
Clearly my interpretation of how aspect around works is mistaken, and the scope of t becomes the Window object instead of the tree itself.
I am hoping there's a quick fix/workaround I can use?
Clarification on my actual purpose
Under certain circumstances, the back-end queried by the store underlying the grid will be unreachable for a short amount of time. The way things are implemented, expanding on nodes of the tree will query the back-end. During the very short window while the back-end is unavailable (which I can easily know from the front-end code), I'd like to ignore clicks on the expandos).
Try to bind tree instance to your function. Something like this:
var myGrid = ...; // features a tree
var myConditional = ...; // some boolean
const condExpand = function(id, skip) {
var deferred = original(id, skip);
return deferred;
}.bind(myGrid )
dojo.aspect.around(myGrid.tree, "expand", function(original) {
return condExpand
});
I'm not sure about where a particular context is lost in your case, but you can play with this to make it work for you.
Update:
Tried to reproduce situation. Below is working example:
const testObject = {
isNumeric: function(number) {
return typeof number === "number"
},
testMethod: function() {
console.log('testMethod', this)
console.log("Is 5 a number: ", this.isNumeric(5))
}
}
const aroundFunc = function(originalTestmethod){
return function(method, args){
// doing something before the original call
console.log("Before", this)
//Here context still corect.
//So bind it to passed here original method:
var deferred = originalTestmethod.bind(this)(method, args)
// doing something after the original call
console.log("After")
return deferred;
}
}
require(['dojo/aspect'], function(aspect) {
aspect.around(testObject, "testMethod", aroundFunc)
testObject.testMethod()
})