Get path value

path-val.js

// via http://www.redotheweb.com/2015/09/18/declarative-imperative-js.html

function getValue(object, propertyName) {
    if (!propertyName) throw new Error('Impossible to set null property');
    return typeof object === 'undefined' ? undefined : object[propertyName];
}

function getNestedValue(object, propertyName) {
    return propertyName.split('.').reduce(getValue, object);
}

var myObj = {
    x: "hi", 
    john: {
        first: "j",
        last: "doe",
        address: {
            street: "103 10th st",
            state: "AZ"
        }
    },
    bill: {
        first: "bill",
        last: "johnson"
    }
};

getNestedValue(myObj, "john.address.street");