Question

I don’t know how can I do this programmatically:

var a={a:"a",b:"b"};
return a.a;
         |
        I want to change this programmatically, how can I do that?

without using eval()?

Answer 1

To dynamically access object properties, you need to invoke the bracket notation form. Like

function foo( prop ) {
    var a = {a:'a', b: 'b'};

    return a[ prop ];
}

foo('b'); // returns 'b'