CODEWITHSUNDEEP
javascriptgetter-setter
devios1
devios1

Reputation: 38025

Can I tell what property a generic getter/setter applies to in its body?

The context (this) is naturally the object that the property is being requested on, but there are no arguments passed to the getter function. I'd like to be able to get the name of the property being requested without using closures but it's looking like that's the only way to do it.

Object.defineProperty( someObj, "prop1", { get: genericGetter } );
Object.defineProperty( someObj, "prop2", { get: genericGetter } );

function genericGetter() {
    // i want to figure out whether this is called on prop1 or prop2
}

Upvotes: 0

Views: 257

Answers (1)

Šime Vidas
Šime Vidas

Reputation: 185943

Can I tell what property a generic getter/setter applies to in its body?

That's not how getters work. A property of an object can either have a value or a get function. If the property has a value, then reading the property:

var x = obj.prop;

returns that value. However, if a property has a get function instead, then reading that property triggers that function. So, you use getters if the value of a certain property has to be computed dynamically, or if you want to perform certain operations whenever the property is read.

For instance, .innerHTML requires a getter, because its value is not stored statically, but computed on access:

var html = div.innerHTML;

Here, the browser has to serialize the DOM structure that is contained within the div element.

So, if you want a .get() function that retrieves various properties (Backbone.js has such a function), then you're not looking for getters.

The simplest implementation of what you want would be:

someObj.getProp = function ( name ) {
    // perform required tasks
    return this[ name ];
};

Upvotes: 2

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