Implementation of recursive 'deepEqual' function as suggested in Eloquent Javascript

deepEqual.js

// deepEqual takes two variables and tests for property/value equality, recursively for objects.
// Idea for function and some examples for testing borrowed from ch.4 in Marijn Haverbeke's "Eloquent Javascript".

function deepEqual(obj1, obj2) {
  if (typeof obj1 === typeof obj2) {

    if (obj1 === obj2) {
      return true;

    } else if (obj1 && obj2) {
      if (typeof obj1 === 'object' && typeof obj2 === 'object') {

        for (var prop in obj1) {
          for (var prop2 in obj2) {
            if (prop === prop2) {

              if (!deepEqual(obj1[prop], obj2[prop2])) {
                return false;
              }
            }
          }
        }
        return true;
      }
    }
  }
  return false;
}

function testDeepEqual() {
  var obj = {here: {is: 'an'}, object: 2};

  console.log('You should see alternating true/false, starting and ending with false.');

  console.log(deepEqual(obj, 2));
  // -> false
  console.log(deepEqual('a string', 'a string'));
  // -> true
  console.log(deepEqual(null, obj));
  // -> false
  console.log(deepEqual(obj, obj));
  // → true
  console.log(deepEqual(obj, {here: 1, object: 2}));
  // → false
  console.log(deepEqual(obj, {here: {is: 'an'}, object: 2}));
  // → true
  console.log(deepEqual(null, undefined));
  // -> false
}

testDeepEqual();