JavaScript ES6+ Features 3

Question 1

What is the result of `[...'hello']`?

Accepted Answer

['h','e','l','l','o']

Answer

The spread operator on a string iterates over each character, producing an array of individual characters.

Question 2

Which statement correctly creates a class with a static method in ES6?

Accepted Answer

class Foo { static bar() {} }

Answer

The `static` keyword before a method definition in a class body creates a method on the class itself, not on instances.

Question 3

What does `Promise.allSettled([p1, p2])` return when `p1` resolves and `p2` rejects?

Accepted Answer

Resolves with an array of {status, value/reason} for both

Answer

`Promise.allSettled` always resolves with an array describing each promise's outcome—fulfilled or rejected—never short-circuits.

Question 4

In ES6 template literals, how do you embed a JavaScript expression?

Accepted Answer

${expression}

Answer

Template literals use `${expression}` syntax inside backtick strings to interpolate any valid JavaScript expression.

Question 5

What is a tagged template literal?

Accepted Answer

A function called with the template's string parts and interpolated values as arguments

Answer

A tagged template literal prepends a function name to the template; the function receives the string parts array and the interpolated values as separate arguments.

JavaScript Practice Test

JavaScript Practice Test

JavaScript ES6+ Features 3