A javascript function to compare (by inference) object, strings, number

equal.js

// test that every value of A exists in B and are equal
// true equality: eq(a,b,1)
// true: eq({b:[1,2]}, {a:1, b:[1,2]})
// false: eq({a:1, b:[1,2]},{b:[1,2]})
// false: eq({b:[1,2]}, {a:1, b:[1,2,3]})
// false: eq({b:[1,2,3]}, {a:1, b:[1,2]})
function eq(a, b, bidirectional){
  if (typeof(a) != typeof(b)) return false;
  if (typeof(a) in {string: 1, number: 1}) return a == b;
  if (a.length != b.length) return false;
  for (var i in a){
    if (!eq(a[i], b[i])) return false;
  }
  if (bidirectional) return eq(b,a); 
  return true;
}