Checking whether something is iterable

Question

In the MDN docs: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...of

The for...of construct is described to be able to

Answer 1

The proper way to check for iterability is as follows:

function isIterable(obj) {
  // checks for null and undefined
  if (obj == null) {
    return false;
  }
  return typeof obj[Symbol.iterator] === 'function';
}

Why this works (iterable protocol in depth): https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Iteration_protocols

Since we are talking about for..of, I assume, we are in ES6 mindset.

Also, don't be surprised that this function returns true if obj is a string, as strings iterate over their characters.