let arr1 = [ 1, 2, 3]; let arr2 = arr1; console.log(arr1); // [1, 2, 3] console.log(arr2); // [1, 2, 3] // append an item to the array arr1.push(4); console.log(arr1); // [1, 2, 3, 4] console.log(arr2); // [1, 2, 3, 4]