JavaScript Array Destructuring and Defaults

Given the following code snippet, what will be the value of a and b after the code is executed?

let a = 111;
let b = 999;
const obj = { a: 23, b: 7, c: 14 };
({ a, b } = obj);

In JavaScript, the spread operator(...) can be used for passing separated data of an ________ into a function.

Consider the following JavaScript code:

const nested = [1, [2, 3], 4];
const [a, [b, c], d] = nested;
console.log(a, b, c, d);

What will be the output of console.log(a, b, c, d)?

The spread operator (...) can be used to create a deep copy of an object in JavaScript.

Describe how array destructuring can be used to swap the values of two variables a and b in JavaScript. Include a brief code example.

Given the following code:

const HP = ['harry','hermion','ron',...['dambeldor','Snape','mackgolagan']]; const [name,...rest] = HP;

What will console.log(rest) output?

The spread operator can be used on non-iterable objects directly without creating a new array.

Explain the difference between the || operator and the ?? (nullish coalescing) operator in JavaScript, particularly focusing on what values they consider 'falsy'.

In the context of function parameters, the ______ parameter must always be the last one defined.

Match the operator with its description:

What is the index and value that will be logged to the console for the second element in the following code snippet?

const arr = ['Newt', 'Tina', 'Jacob Kowalski', 'Queenie']; for(const item of arr.entries()) {console.log(item)}

In enhanced object literals, the shorthand for assigning a property named seasons with the value of the variable seasons is simply _________.

Consider the following code: const seasonNum = [1,2,3,4,5]; const seasons = { [seasonNum]: { episode: 13, realeased: {First: '20 September 2008', Last: '13 December 2008'} } }; What does seasons[seasonNum].episode evaluate to?

The following code snippet will cause an error because the seasonNum array is used as a property key:

const seasonNum =[1,2,3,4,5]; const seasons = { [seasonNum]: { episode:13, realeased:{First:'20 September 2008 ', Last:'13 December 2008'} } };

In the serie object, how is the getInfo method defined using ES6 syntax, and what does it log to the console?

Which of the following statements accurately describes the behavior of the nullish coalescing operator (??) in JavaScript, as demonstrated by the example serie.risoto?.(10,12) ?? console.log('the method does not exist');?

Given the code:

const openinghours = {
  sat: { open: '10 am', close: '10 pm' },
  sun: { open: '11 am', close: '9 pm' },
  mon: { open: '6 am', close: '12 pm', shift: 'harry' }
};

const values = Object.values(Object.keys(Object.values(openinghours)));
console.log(values);

The values variable will contain an array of the opening and closing times for each day.

Explain how the concept of optional chaining (?.) and nullish coalescing (??) operators can be combined to safely access nested object properties and provide a default value if the property is missing.

In JavaScript, the Object.entries() method returns an array of a given object's own enumerable string-keyed property ______, in the format [key, value].

Match the following JavaScript code snippets with their described outcomes: