Advanced Patterns — Series 2

Preview — 3 of 10 questions

What is the output of the following code?

javascript

const obj = { value: 42 };
const { value: x = 10, label: y = 'default' } = obj;
console.log(x, y);

A42 undefined

B42 'default'

C10 'default'

DReferenceError

What will the following code log?

javascript

function makeCounter() {
  let count = 0;
  return {
    inc() { count++; },
    get() { return count; },
  };
}

const a = makeCounter();
const b = makeCounter();
a.inc(); a.inc();
b.inc();
console.log(a.get(), b.get());

A2 1

B3 3

C2 2

D1 1

What is logged?

javascript

const arr = [1, 2, 3];
const [first, ...rest] = arr;
rest.push(4);
console.log(arr, rest);

A[1, 2, 3, 4] and [2, 3, 4]

B[1, 2, 3] and [2, 3, 4]

C[1, 2, 3] and [2, 3]

D[1, 2, 3, 4] and [2, 3]

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