How to access object property from inside class function [duplicate]

Answer 1

I learned this the hard way, you have to be careful with this. It always refers to the this in the current scope, not it's containing object. Whenever you wrap something in function() { ... }, this becomes of a different scope. In your case, duplicate the object to a local variable and manipulate it's .data property.

function File(data){
    this.data = data;
    var file = this; //call the variable whatever you want
    this.update = function (callback){
        var set = function(ajaxData){
            file.data = ajaxData.PcbFile;
        }
        getPcbFile(data.id, function(ajaxData){
            set(ajaxData);
            callback();
        });
    };
}