I was looking at the source code of a JavaScript library and encountered something like this in a class definition:
var MyClass = function() {
function doSomething() {
// function definition
}
this.doSomething = function() {
doSomething();
};
}
So, my question is: is there any reason someone would do this instead of simply assigning the function to the object method like this:
this.doSomething = doSomething;
It depends on exactly what doSomething is actually doing. There is a difference in how this will be bound within the function. If you call it as per your example, it won't have this bound to the object, whereas if you call it with it assigned directly to a property, then this will be bound to the instance:
var MyClass = function() {
this.n = "Bob";
function doSomething() {
console.log(this.n);
}
this.doSomething = function() {
doSomething();
};
this.doSomethingDirect = doSomething;
}
var x = new MyClass();
x.doSomething(); //undefined
x.doSomethingDirect(); //"Bob"