Try this:
var Predicate = breeze.Predicate;
var baseQuery = EntityQuery.from("Something");
var pred1 = new Predicate("age", ">", 30);
var pred2 = new Predicate("sex", "==", 'M');
var pred3 = new Predicate("jobStartDate", ">=", new Date(2000,1,1));
var pred4 = new Predicate("exemptStatus", "==", 1);
var compositePred = pred1.and(pred2).and(pred3).or(pred4);
var query = baseQuery.where(compositePredicate);
myEntityManager.executeQuery(query);
or
var compositePred = Predicate.and(pred1, pred2, pred3).or(pred4);