Question

What will the code below output to the console and why?

var arr1 = "john".split('');
var arr2 = arr1.reverse();
var arr3 = "jones".split('');
(arr3);
("array 1: length=" + + " last=" + (-1));
("array 2: length=" + + " last=" + (-1));

Answer 1

The code does array manipulation in JavaScript and should output the length and last elements of the arrays arr1 and arr2, which will be the same as they reference the same reversed array. However, arr3 would have different values since it is a separate array created from another string. Nevertheless, the logging statements provided are incomplete and will not execute correctly as written.

Step-by-step explanation:

The given code is a JavaScript snippet that performs operations on arrays derived from strings. First, the string 'john' is split into an array arr1 with the split method, resulting in ['j', 'o', 'h', 'n']. Then, arr1 is reversed, resulting in ['n', 'h', 'o', 'j']. Due to JavaScript's reference behavior for objects (which includes arrays), arr2 points to the same array as arr1 after the reverse operation; thus, both arr1 and arr2 are ['n', 'h', 'o', 'j'] after the reverse. Afterwards, the string 'jones' is split into a new array arr3, resulting in ['j', 'o', 'n', 'e', 's'].

However, the logging statements seem to be incomplete. Assuming the correct syntax would be console.log("array 1: length=" + arr1.length + " last=" + arr1[arr1.length - 1]); and similarly for arr2 and arr3, the output to the console for arr1 and arr2 would be 'array 1: length=4 last=j' and 'array 2: length=4 last=j', respectively (since both arr1 and arr2 reference the same reversed array).