Using array value as object field name

Question

If I have an array and an object is it possible to use the array values as field name to get the object field value?

Like this:

var x = ['foo', 'bar'],
    y = {
        foo: 'foo,foo',
        bar: 'bar,bar'
    }

for (var i = 0, l = x.length; i < l; i++) {
    console.log(y.x[i]);
    // Uncaught TypeError: Cannot read property '0' of undefined 
}

Except, this doesn't work.

Demo

Update

what if one of the object fields is a method like :

y = {
    foo: 'foo,foo',
    bar: function () {
        alert('');
    }
}

Arun P Johny · Accepted Answer · 2013-11-23 03:26:24Z

4

you need to use bracket notation as you are dealing with a variable key

console.log(y[x[i]]);

Demo: Fiddle

y.x[i] tries to read a property x of y which does not exits so the [0] throws an error.

answered Nov 23, 2013 at 3:26

Arun P Johny

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7 Comments

Mina Gabriel Over a year ago

what would you do with functions

Mina Gabriel Over a year ago

yes if one of them is a function i notice it will yield the function as string

Arun P Johny Over a year ago

@MinaGabriel do you want to invoke the function

Arun P Johny Over a year ago

just add () to the function reference like y[x[i]]()

Arun P Johny Over a year ago

@MinaGabriel see jsfiddle.net/arunpjohny/VLn69/3 or jsfiddle.net/arunpjohny/VLn69/4

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