How to add an array of values to a Set

Question

The old school way of adding all values of an array into the Set is:

// for the sake of this example imagine this set was created somewhere else 
// and I ca         


        

Answer 1

How about using the spread operator to easily blend your new array items into an existing set?

const mySet = new Set([1,2,3,4])
const additionalSet = [5,6,7,8,9]
mySet = new Set([...mySet, ...additionalSet])

JSFIDDLE