get object field value with string nested pattern
function findProp(obj, prop, defval){
if (typeof defval == 'undefined') defval = null;
prop = prop.split('.');
for (var i = 0; i < prop.length; i++) {
if(typeof obj[prop[i]] == 'undefined')
return defval;
obj = obj[prop[i]];
}
return obj;
}
var data = {"id":1,"name":"abc","address":{"streetName":"cde","streetId":2}};
var props = 'address.streetName';
alert('The value of ' + props + ' is ' + findProp(data, props));