JavaScript - Is Nested Object Property Defined
// FROM: http://jsfiddle.net/DWefK/5/
var obj = {
a: {
b: ''
}
};
function defined(ref, strNames) {
var name;
var arrNames = strNames.split('.');
while (name = arrNames.shift()) {
if (!ref.hasOwnProperty(name)) return false;
ref = ref[name];
}
return true;
}
console.log( defined( obj, 'a.b' ) );