JS array trouble with concat code example

Example 1: es6 concat array

let fruits = ["apples", "bananas"];
let vegetables = ["corn", "carrots"];
let produce = [...fruits, ...vegetables];
//["apples","bananas","corn","carrots"]

Example 2: concat js mdn

const array1 = ['a', 'b', 'c'];
const array2 = ['d', 'e', 'f'];
const array3 = array1.concat(array2);

console.log(array3);
// expected output: Array ["a", "b", "c", "d", "e", "f"]