Pretty much everything is in the title but i'll give you an example :
// i can't know the content of this string but for the exemple she's here
let str = 'elem-0, elem-1, elem-2, elem-3';
// how to properly write this line because this line is not write in an array 'destructuring way'
let array = str.split(',')[0];
// return me : "elem-0" (and he has to)
console.log(array);