How to get properties of the object subjected to event using Fabric.js?

问题

Using Fabric.js 1.1.6, I have the following:

var rect = new fabric.Rect({});
rect.on('moving', function(obj) {
    // I want to retrieve and set properties from the
    // object rect from inside this event function
});

Is it possible to retrieve and modify the rect properties from inside the function called by the event?
If it is, how do I do that?
If it is not, any suggestions on how could I modify rect properties from inside the event function?

Thank you in advance!

Update: The above question is correctly answered by @plalx, but I actually have this in a greater context:

function SomeClass()
{
    this.rect = new fabric.Rect({});
    this.rect.on('moving', function(obj) {
        // here, this.rect is undefined
    });
}

Well, in the latter context, I can't only use this.rect inside the function, because there this refers to the function, not to SomeClass.

How about now, what are the answers for the three questions above?

回答1:

"Is it possible to retrieve and modify the rect properties from inside the function called by the event?"

Not only it is possible but it is very simple ;) You should read about closures in JavaScript.

For question #1

var rect = new fabric.Rect({});
rect.on('moving', function(obj) {
    rect.someProperty = 'test';
});

For question #2

function SomeClass() {
    var rect = this.rect = new fabric.Rect({});

    this.rect.on('moving', function(obj) {
        // here, this.rect is undefined
        rect.someProperty;
    });
}

来源：https://stackoverflow.com/questions/15916603/how-to-get-properties-of-the-object-subjected-to-event-using-fabric-js

标签

javascript

events

fabricjs