I have two objects:

object1={
   type: 'obj1',
   nName: 'nName'
}

object2={
   type: 'obj2',
   pName: 'pName'
}

In my js code, I have:

object=GET_OBJECT();

The GET_OBJECT() method returns either object1 or object2, then, I would like to access the object's name attribute which is either nName or pName.

I have one method which will get the name (pName or nName) of the returned object:

function getName(Object, name){
      return object.name;
}

where I would like the name to be a variable, so that I can access the pName or nName in this way:

object=GET_OBJECT();

var name='';

if(object.type=='obj1')
   name='nName';
else
   name='pName';

var finalName=getName(object, name);

But seems it won't work since in:

function getName(Object, name){
          return object.name;
    }

name is a variable. In JS, is there any way to access attribute as a variable?

I have two objects:

object1={
   type: 'obj1',
   nName: 'nName'
}

object2={
   type: 'obj2',
   pName: 'pName'
}

In my js code, I have:

object=GET_OBJECT();

The GET_OBJECT() method returns either object1 or object2, then, I would like to access the object's name attribute which is either nName or pName.

I have one method which will get the name (pName or nName) of the returned object:

function getName(Object, name){
      return object.name;
}

where I would like the name to be a variable, so that I can access the pName or nName in this way:

object=GET_OBJECT();

var name='';

if(object.type=='obj1')
   name='nName';
else
   name='pName';

var finalName=getName(object, name);

But seems it won't work since in:

function getName(Object, name){
          return object.name;
    }

name is a variable. In JS, is there any way to access attribute as a variable?

• javascript
• javascript-framework

2 Answers 2

Try like this:

function getName(Object, name) {
    return Object[name];
}

AS many times before I wonder why people provide solutions and not knowledge. Otherwise the asker will repeat the same mistakes over and over.

The original code uses a function to retrieve an attribute. It is assumed that it is possible to use the parameter to invoke the parameter. In more technical words, Dot notation is being used which must be a valid JavaScript identifier. Tha name after the dot is the pointer the content. Therefore getName always is accessing the attribute name which is likely to be undefined.

The solution shown uses Bracket notation in which uses the content of the parameter (which may not exist) as identifier and then, it resolves the content and this is why it actually works.

Dot notation is faster and easier to read and would be adviced if both are valid options. Bracket notation is to be used when you need resolving in run time. That is what happens when you define setters and getters internally. The following code will use the string passed to ensure (using bracket notation) that whenever you use the identifier by dot notation will call the functions passed.

function myClass(){
        //setX and getX should be also defined previous to this
        this.__defineSetter__("x",this.setX);    
        this.__defineGetter__("x",this.getX); 
        //Object.defineProperty can also be used
};

var tObject = new myClass();
tObject.x = 10; //Getter being called