returns an object describing any missing attributes nested within an object

_.missing

_.mixin({
    missing: function(obj, requirements) {
        var missing = {};
        _.each(requirements, function(requirement, field) {
            if (_.isNull(obj[field]) || _.isUndefined(obj[field])) {
                missing[field] = false;
                return;
            }
            if (typeof obj[field] === 'object') {
                potential = _.missing(obj[field], requirement);
                if (typeof potential !== 'null' && (typeof potential == 'object' && _.size(potential) > 0)) {
                    missing[field] = potential;
                }
            }
        });

        return missing;
    }
});

var context = { one: {}, two: { one: 'ONE', two: 'TWO', three: 'THREE' } };
var requirements = { one: { two: true } };

var missing = _.missing(context, requirements);

console.log(missing);