Access property via it's keyPath in Javascript?

I have

data = 
{
    'first': {
        'number': 1,
        'text': 'Ya.'
    },
    'second': {
        'number': 10,
        'text': 'Da.'
    }
};

And I really want to access it like:

number = data['first.number'];

Actually in a more flexible way, like:

numberOrText = data[memberName+'.'+propertyName];

Is there any lightweight library, or snippet you can suggest? This is - https://github.com/martinvl/KVCObject - so cool, but a bit overhead for this.

Based on @dandavis pretty simple suggestions, I can set up accessors as prototype properties.

No eval, also leave Object.prototype untouched in terms of enumerating using Object.defineProperty.

The solution actually goes like this:

function stringContains(string, value)
{ return string.indexOf(value) != -1; }

Object.defineProperty(Object.prototype, "setValueForKey", { value: function(value, key)
{ this[key] = value; }});

Object.defineProperty(Object.prototype, "setValueForKeyPath", { value: function(value, keyPath)
{
    if (keyPath == null) return;
    if (stringContains(keyPath, '.') == false) { this.setValueForKey(value, keyPath); return; }

    var chain = keyPath.split('.');
    var firstKey = chain.shift();
    var shiftedKeyPath = chain.join('.');

    this[firstKey].setValueForKeyPath(value, shiftedKeyPath);
}});

Object.defineProperty(Object.prototype, "getValueForKey", { value: function(key)
{ return this[key]; }});

Object.defineProperty(Object.prototype, "getValueForKeyPath", { value: function(keyPath)
{
    if (keyPath == null) return;
    if (stringContains(keyPath, '.') == false) { return this.getValueForKey(keyPath); }

    var chain = keyPath.split('.');
    var firstKey = chain.shift();
    var shiftedKeyPath = chain.join('.');

    return this[firstKey].getValueForKeyPath(shiftedKeyPath);
}});

Test are fine:

data = {
    'name' : 'data',
    'first': {
        'number': 1,
        'text': 'Ya.',
        'meta' : {
            'lang' : 'en'
        }
    },
    'second': {
        'number': 10,
        'text': 'Ba.',
        'meta' : {
            'lang' : 'en'
        }
    },
    'third': {
        'number': 100,
        'text': 'Da.',
        'meta' : {
            'lang' : 'hu'
        }
    }
};

data.setValueForKey('chunk', 'name');
data.setValueForKeyPath('blob', 'name');

var thirdLanguage = data.getValueForKeyPath('third.meta.lang');
data.setValueForKeyPath(thirdLanguage, 'first.meta.lang');
data.setValueForKeyPath(thirdLanguage, 'second.meta.lang');

log(data);

Output is the same with hu as language in every data member.