JavaScript Iterable : Object

An iterable object is any object that returns a function that produces an Iterator for its Symbol.iterator property. You can loop over all values in an iterable object by using a for (var value of iterable) { } loop. See Iterator for more details.

ECMAScript 2015 Spec

Instance Indexers

this[Symbol.iterator] : Function<Iterator>

Returns a function that produces an Iterator for this object.

Example:

// Arrays are a built in Iterable object
var arr = ['a', 'b', 'c'];

// Use for (... of ...) loop to get the values of an iterable
for (var x of arr) {
  console.log(x);
} 

// Under the covers, for (... of ...) does the following: 
var iterator = arr[Symbol.iterator]();
var current = iterator.next();
while (!current.done) {
  console.log(current.value);
  current = iterator.next();
}

Run

Results:

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