Javascript - 分配函数返回的引用值

Question

I have a function of the prototype of an object called getComponent which returns this.components[name]

function Foo()
{
    this.components = {"Scripts": [...], "Sprites": [...], "States": {...}, etc };
}

Foo.prototype.getComponent = function(name)
{
    return this.components[name];
}

Then I have some code that gets a component and sets it to something else...

var foo = new Foo();
foo.getComponent("Sprites") = [];

This obviously raises the Uncaught ReferenceError: Invalid left-hand side in assignment .

Is there anyway to set the value of the returned value?

I don't want to access the objects variables directly: foo.components.Sprites = [] .

Thanks in advance,

David

Answer 1

No.

You can assign values to variables, constants and to the properties of objects.

A function returns a value. It never returns a variable, constant or property (not even if it reads one of those to get the value).

---

Either:

• create a setComponent method which takes two arguments and assigns the value of the second one to the property.
• rename your method to component and have it take an optional second argument and then act as either setComponent or getComponent depending on how many arguments were passed.