Learn ECMAScript - Second Edition

Using the rest operator in an array destructuring assignment

We can prefix the last variable of an array destructuring expression using the ... token. In this case, the variable is always converted into an array object that holds the rest of the values of the iterable object, if the number of other variables is less than the values in the iterable object.

Consider this example to understand it:

   let [a, ...b] = [1, 2, 3, 4, 5, 6];
   console.log(a);
   console.log(Array.isArray(b));
   console.log(b);

The output is as follows:

   1
   true
   2,3,4,5,6

In the previous example code, you can see that the b variable is converted into an array, and it holds all the other values of the right-hand side array.

Here the ... token is called the rest operator ...