Javascript ... three dots

 https://oprearocks.medium.com/what-do-the-three-dots-mean-in-javascript-bc5749439c9a

const numbers1 = [1, 2, 3, 4, 5];const numbers2 = [ ...numbers1, 1, 2, 6,7,8]; // this will be [1, 2, 3, 4, 5, 1, 2, 6, 7, 8]