--description--

To pass the quiz, you must correctly answer at least 18 of the 20 questions below.

--quizzes--

--quiz--

--question--

--text--

Which one of these will create a String object?

--distractors--

String({ "Hello World" });

String("Hello World");

"Hello World".toString();

--answer--

new String("Hello World");

--question--

--text--

How can you convert a String object into a string literal?

--distractors--

With the String() constructor.

With the .stringify() method.

Enclose the String object in double quotes.

--answer--

With the .toString() method.

--question--

--text--

Why can you use methods like .length, .repeat(), .concat(), and .slice() on a string primitive in JavaScript?

--distractors--

Those methods exist natively on string primitives.

String primitives are stored as objects internally.

JavaScript temporarily converts the string primitive to an array.

--answer--

JavaScript temporarily wraps the string primitive in a String object.

--question--

--text--

What will the following code log to the console?

let stringArray = [8, 9, 10].toString();
console.log(stringArray);

--distractors--

[8,9,10]

["8", "9", "10"]

"8", "9", "10"

--answer--

"8,9,10"

--question--

--text--

Which of the following returns a Number object from the string "123"?

--distractors--

Object("123")

"123".toNumber()

Number("123")

--answer--

new Number("123")

--question--

--text--

What will Number(true) and Number(false) return, respectively?

--distractors--

undefined and undefined

NaN and NaN

true and false

--answer--

1 and 0

--question--

--text--

What will Number(undefined) and Number(null) return, respectively?

--distractors--

NaN and NaN

0 and 0

undefined and null

--answer--

NaN and 0

--question--

--text--

Which of the following is the best name for a boolean variable that checks if a user is allowed to do something on your website?

--distractors--

getPermission

handlePermission

permission

--answer--

hasPermission

--question--

--text--

Which of the following is the best name for a function that runs when a user submits a form?

--distractors--

hasSubmitted

formSubmit

didSubmit

--answer--

handleSubmit

--question--

--text--

What is a sparse array?

--distractors--

An array where one or more indices have a value of null.

An array where one or more indices have a value of undefined.

An array where one or more indices have a value of an empty object literal.

--answer--

An array where one or more indices are not assigned a value.

--question--

--text--

In which of the following examples will arr NOT be a sparse array?

--distractors--

const arr = new Array(5);

const arr = [1, 2, 3];
arr[4] = 4;

const arr = [1, 2, 3, , 5];

--answer--

const arr = Array.from({ length: 5 });

--question--

--text--

What is the primary purpose of a linter?

--distractors--

To format code automatically.

To optimize code for performance.

To create documentation for code.

--answer--

To detect potential errors and issues in code.

--question--

--text--

What is a benefit of using a formatter in a codebase?

--distractors--

They allow developers to compile code more efficiently.

They convert code to a specific programming language.

They detect logical errors.

--answer--

They ensure a consistent code style.

--question--

--text--

In JavaScript, who or what is typically responsible for allocating memory to variables?

--distractors--

The developer.

The operating system.

The server.

--answer--

The runtime engine.

--question--

--text--

What will be logged to the console in the following code?

function trackTotal(initialValue) {
  let total = initialValue;
  return function(increment) {
    total += increment;
    return total;
  };
}

let track = trackTotal(1);
console.log(track(2));
console.log(track(3));

--distractors--

2
5

2
3

5
6

--answer--

3
6

--question--

--text--

What is hoisting in JavaScript?

--distractors--

Raising errors to the top of the code.

The process of creating new variables.

Automatically moving var declarations to the top of the block.

--answer--

The process of moving variable declarations to the top of their scope.

--question--

--text--

Why is using the var keyword considered bad practice in modern JavaScript?

--distractors--

They're slower than let and const.

They cause syntax errors.

They don't allow type checking.

--answer--

They're accessible outside their block.

--question--

--text--

What is the purpose of modules in JavaScript?

--distractors--

To improve code performance.

To make code more difficult to understand.

To create new programming languages.

--answer--

To organize code into reusable units.

--question--

--text--

How do you add an app.js script as a module in an HTML document?

--distractors--

<script type="module/javascript" src="app.js"></script>

<script src="app.js"></script>

<script src="app.js" module></script>

--answer--

<script type="module" src="app.js"></script>

--question--

--text--

Which of the following examples exports the calculateSum function from a utils.js module and properly imports and uses it in an app.js file?

--distractors--

// utils.js
export default function calculateSum(a, b) {
  return a + b;
}

// app.js
import { calculateSum } from './utils.js';
console.log(calculateSum(2, 3));

// utils.js
export function calculateSum(a, b) {
  return a + b;
}

// app.js
import calculateSum from './utils.js';
console.log(calculateSum(2, 3));

// utils.js
function calculateSum(a, b) {
  return a + b;
}

export default calculateSum;

// app.js
import * as utils from './utils.js';
console.log(utils.calculateSum(2, 3));

--answer--

// utils.js
export function calculateSum(a, b) {
  return a + b;
}

// app.js
import { calculateSum } from './utils.js';
console.log(calculateSum(2, 3));