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 iterate over "iterable" objects. But is there a good way of deciding whether an object is iterable?

I've tried to find common properties for arrays, iterators and generators, but have been unable to do so.

Aside from doing a for ... of in a try block and checking for type errors, is there a clean way of doing this?

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.