Question

If I have a javascript function, it is possible that I do not return a value from every code path, e.g:

function f()
{
  if (checkSomething())
  {
    return 42;
  }
  // no return statement here
}

Is this valid javascript or does it only work by chance (i.e. might there be problems when run in some browsers)?

Answer 1

Yes, it is valid javascript. If checkSomething() evaluates to false, it will return undefined.

See http://developer.mozilla.org/en/JavaScript/Reference/Functions_and_function_scope for more details.

Althought, you should note that returning different types of data (In this case, an integer or undefined) is bad practice.