LinkedIn JavaScript Skill Assessment Answers 2024

100% Free Updated LinkedIn JavaScript Skill Assessment Certification Exam Questions & Answers.

JavaScript Skill Assessment Details:

  • 15 multiple-choice questions
  • 1.5 minutes per question
  • Score in the top 30% to earn a badge

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Which operator returns true if the two compared values are not equal?

  • <>
  • ~
  • ==!
  • !==

How is a forEach statement different from a for statement?

  • Only a for statement uses a callback function.
  • A for statement is generic, but a forEach statement can be used only with an array.
  • Only a forEach statement lets you specify your own iterator.
  • A forEach statement is generic, but a for statement can be used only with an array.

Review the code below. Which statement calls the addTax function and passes 50 as an argument?
function addTax(total) {
return total * 1.05;
}

  • addTax = 50;
  • return addTax 50;
  • addTax(50);
  • addTax 50;

How would you use this function to find out how much tax should be paid on $50?
(Version 2, possibly an updated version)

function addTax(total) {
return total * 1.05;
}

  • addTax($50);
  • return addTax 50;
  • addTax(50);
  • addTax 50;

Which statement is the correct way to create a variable called rate and assign it the value 100?

  • let rate = 100;
  • let 100 = rate;
  • 100 = let rate;
  • rate = 100;

Which statement creates a new Person object called “student”?

  • var student = new Person();
  • var student = construct Person;
  • var student = Person();
  • var student = construct Person();

When would the final statement in the code shown be logged to the console?
let modal = document.querySelector(‘#result’);
setTimeout(function(){
modal.classList.remove(‘hidden);
}, 10000);
console.log(‘Results shown’);

  • after 10 second
  • after results are received from the HTTP request
  • after 10000 seconds
  • immediately

When would ‘results shown’ be logged to the console?
(Version 2, possibly an updated version)

let modal = document.querySelector(‘#results’);
setTimeout(function () {
modal.classList.remove(‘hidden’);
}, 10000);

  • immediately
  • after results are received from the HTTP request
  • after 10 second
  • after 10,000 seconds

You’ve written the code shown to log a set of consecutive values, but it instead results in the value 5, 5, 5, and 5 being logged to the console. Which revised version of the code would result in the value 1, 2, 3 and 4 being logged?
for (var i = 1; i <= 4; i++) {
setTimeout(function () {
console.log(i);
}, i * 10000);
}

  • for (var i=1; i<=4; i++){ (function(i){ setTimeout(function(){ console.log(j); }, j*1000); })(j) }
  • while (var i=1; i<=4; i++) { setTimeout(function() { console.log(i); }, i*1000); }
  • for (var i=1; i<=4; i++) { (function(j) { setTimeout(function(){ console.log(j); }, j*1000); })(i) }
  • for (var j=1; j<=4; j++) { setTimeout(function() { console.log(j); }, j*1000); }

How does a function create a closure?

  • It reloads the document whenever the value changes.
  • It returns a reference to a variable in its parent scope.
  • It completes execution without returning.
  • It copies a local variable to the global scope.

Which statement creates a new function called discountPrice?

  • let discountPrice = function(price) { return price * 0.85; };
  • let discountPrice(price) { return price * 0.85; };
  • let function = discountPrice(price) { return price * 0.85; };
  • discountPrice = function(price) { return price * 0.85; };

What is the result in the console of running the code shown?
var Storm = function () {};
Storm.prototype.precip = ‘rain’;
var WinterStorm = function () {};
WinterStorm.prototype = new Storm();
WinterStorm.prototype.precip = ‘snow’;
var bob = new WinterStorm();
console.log(bob.precip);

  • Storm()
  • undefined
  • ‘rain’
  • ‘snow’

You need to match a time value such as 12:00:32. Which of the following regular expressions would work for your code?

  • /[0-9]{2,}:[0-9]{2,}:[0-9]{2,}/
  • /\d\d:\d\d:\d\d/
  • /[0-9]+:[0-9]+:[0-9]+/
  • / : : /

What is the result in the console of running this code?
‘use strict’;
function logThis() {
this.desc = ‘logger’;
console.log(this);
}
new logThis();

  • undefined
  • window
  • {desc: “logger”}
  • function

How would you reference the text ‘avenue’ in the code shown?
let roadTypes = [‘street’, ‘road’, ‘avenue’, ‘circle’];

  • roadTypes.2
  • roadTypes[3]
  • roadTypes.3
  • roadTypes[2]

What is the result of running this statement?
console.log(typeof(42));

  • ‘float’
  • ‘value’
  • ‘number’
  • ‘integer’

Which property references the DOM object that dispatched an event?

  • self
  • object
  • target
  • source

You’re adding error handling to the code shown. Which code would you include within the if statement to specify an error message?
function addNumbers(x, y) {
if (isNaN(x) || isNaN(y)) {
}
}

  • exception(‘One or both parameters are not numbers’)
  • catch(‘One or both parameters are not numbers’)
  • error(‘One or both parameters are not numbers’)
  • throw(‘One or both parameters are not numbers’)

Which method converts JSON data to a JavaScript object?

  • JSON.fromString();
  • JSON.parse()
  • JSON.toObject()
  • JSON.stringify()

When would you use a conditional statement?

  • When you want to reuse a set of statements multiple times.
  • When you want your code to choose between multiple options.
  • When you want to group data together.
  • When you want to loop through a group of statement.

What would be the result in the console of running this code?
for (var i = 0; i < 5; i++) {
console.log(i);
}

  • 12345
  • 1234
  • 01234
  • 012345

Which Object method returns an iterable that can be used to iterate over the properties of an object?

  • Object.get()
  • Object.loop()
  • Object.each()
  • Object.keys()

After the following code, what is the value of a.length?
var a = [‘dog’, ‘cat’, ‘hen’];
a[100] = ‘fox’;
console.log(a.length);

  • 101
  • 3
  • 4
  • 100

What is one difference between collections created with Map and collections created with Object?

  • You can iterate over values in a Map in their insertion order.
  • You can count the records in a Map with a single method call.
  • Keys in Maps can be strings.
  • You can access values in a Map without iterating over the whole collection.
  • Map.prototype.size returns the number of elements in a Map, whereas Object does not have a built-in method to return its size.

What is the value of dessert.type after executing this code?
const dessert = { type: ‘pie’ };
dessert.type = ‘pudding’;

  • pie
  • The code will throw an error.
  • pudding
  • undefined

0 && hi

  • ReferenceError
  • True
  • 0
  • false

Which of the following operators can be used to do a short-circuit evaluation?

  • ++
  • ==
  • ||

Which statement sets the Person constructor as the parent of the Student constructor in the prototype chain?

  • Student.parent = Person;
  • Student.prototype = new Person();
  • Student.prototype = Person;
  • Student.prototype = Person();

Why would you include a “use strict” statement in a JavaScript file?

  • to tell parsers to interpret your JavaScript syntax loosely
  • to tell parsers to enforce all JavaScript syntax rules when processing your code
  • to instruct the browser to automatically fix any errors it finds in the code
  • to enable ES6 features in your code

Which Variable-defining keyword allows its variable to be accessed (as undefined) before the line that defines it?

  • all of them
  • const
  • var
  • let

Which of the following values is not a Boolean false?

  • Boolean(0)
  • Boolean(“”)
  • Boolean(NaN)
  • Boolean(“false”)

Which of the following is not a keyword in JavaScript?

  • this
  • catch
  • function
  • array

Which variable is an implicit parameter for every function in JavaScript?

  • Arguments
  • args
  • argsArray
  • argumentsList

For the following class, how do you get the value of 42 from an instance of X?
class X {
get Y() {
return 42;
}
}

  • x.get(‘Y’)
  • x.Y
  • x.Y()
  • x.get().Y

What is the result of running this code?
sum(10, 20);
diff(10, 20);
function sum(x, y) {
return x + y;
}

let diff = function (x, y) {
return x – y;
};

  • 30, ReferenceError, 30, -10
  • 30, ReferenceError
  • 30, -10
  • ReferenceError, -10

Why is it usually better to work with Objects instead of Arrays to store a collection of records?

  • Objects are more efficient in terms of storage.
  • Adding a record to an object is significantly faster than pushing a record into an array.
  • Most operations involve looking up a record, and objects can do that better than arrays.
  • Working with objects makes the code more readable.

Which statement is true about the “async” attribute for the HTML script tag?

  • It can be used for both internal and external JavaScript code.
  • It can be used only for internal JavaScript code.
  • It can be used only for internal or external JavaScript code that exports a promise.
  • It can be used only for external JavaScript code.

How do you import the lodash library making it top-level Api available as the “_” variable?

  • import _ from ‘lodash’;
  • import ‘lodash’ as _;
  • import ‘_’ from ‘lodash;
  • import lodash as _ from ‘lodash’;

What does the following expression evaluate to?
[] == [];

  • True
  • undefined
  • []
  • False

What is the name of a function whose execution can be suspended and resumed at a later point?

  • Generator function
  • Arrow function
  • Async/ Await function
  • Promise function

What will this code print?
f2();

  • 2
  • 1
  • Nothing – this code will throw an error.
  • undefined

Which statement is true about Functional Programming?

  • Every object in the program has to be a function.
  • Code is grouped with the state it modifies.
  • Date fields and methods are kept in units.
  • Side effects are not allowed.

Your code is producing the error: TypeError: Cannot read property ‘reduce’ of undefined. What does that mean?

  • You are calling a method named reduce on an object that’s declared but has no value.
  • You are calling a method named reduce on an object that does not exist.
  • You are calling a method named reduce on an empty array.
  • You are calling a method named reduce on an object that’s has a null value.

How many prototype objects are in the chain for the following array?
let arr = [];

  • 3
  • 2
  • 0
  • 1

Which choice is not a unary operator?

  • typeof
  • delete
  • instanceof
  • void

What type of scope does the end variable have in the code shown?
var start = 1;
if (start === 1) {
let end = 2;
}

  • conditional
  • block
  • global
  • function

What will the value of y be in this code:
const x = 6 % 2;
const y = x ? ‘One’ : ‘Two’;

  • One
  • undefined
  • TRUE
  • Two

Which keyword is used to create an error?

  • throw
  • exception
  • catch
  • error

What’s one difference between the async and defer attributes of the HTML script tag?

  • The defer attribute can work synchronously.
  • The defer attribute works only with generators.
  • The defer attribute works only with promises.
  • The defer attribute will asynchronously load the scripts in order.

The following program has a problem. What is it?
var a;
var b = (a = 3) ? true : false;

  • The condition in the ternary is using the assignment operator.
  • You can’t define a variable without initializing it.
  • You can’t use a ternary in the right-hand side of an assignment operator.
  • The code is using the deprecated var keyword.

This program has a problem. What is it?
(Version 2, possibly an updated version)

var a;
var b = (a = 3) ? true : false;

  • You cannot use a ternary operator in the right-hand side of an assignment.
  • You cannot define a variable without initializing it first.
  • The condition in the ternary statement is using the assignment operator.
  • The code is using the deprecated var keyword.

Which statement references the DOM node created by the code shown?
<p class=”pull”>lorem ipsum</p>

  • Document.querySelector(‘class.pull’)
  • document.querySelector(‘.pull’);
  • Document.querySelector(‘pull’)
  • Document.querySelector(‘#pull’)

What value does this code return?
let answer = true;
if (answer === false) {
return 0;
} else {
return 10;
}

  • 10
  • true
  • false
  • 0

What is the result in the console of running the code shown?
var start = 1;
function setEnd() {
var end = 10;
}
setEnd();
console.log(end);

  • 10
  • 0
  • ReferenceError
  • undefined

What will this code log in the console?
function sayHello() {
console.log(‘hello’);
}console.log(sayHello.prototype);

  • undefined
  • “hello”
  • an object with a constructor property
  • an error message

Which collection object allows unique value to be inserted only once?

  • Object
  • Set
  • Array
  • Map

What two values will this code print?
function printA() {
console.log(answer);
var answer = 1;
}
printA();
printA();

  • 1 then 1
  • 1 then undefined
  • undefined the undefined
  • undefined the 1

For the following class, how do you get the value of 42 from “X” ?
class X {
get Y() {
return 42;
}
}
var x = new X();

  • x.Y
  • x.Y()
  • x.get(‘Y’)
  • x.get().Y

How does the forEach() method differ from a for statement?

  • forEach allows you to specify your own iterator, whereas for does not.
  • forEach can be used only with strings, whereas for can be used with additional data types.
  • forEach can be used only with an array, whereas for can be used with additional data types.
  • for loops can be nested; whereas forEach loops cannot.

What will be logged to the console?
‘use strict’;
function logThis() {
this.desc = ‘logger’;
console.log(this);
}
new logThis();

  • undefined
  • function
  • windows
  • {desc: “logger”}

Which choice is an incorrect way to define an arrow function that returns an empty object?

  • => ({})
  • => {}
  • => { return {};}
  • => (({}))

Why might you choose to make your code asynchronous?

  • to start tasks that might take some time without blocking subsequent tasks from executing immediately
  • to ensure that tasks further down in your code are not initiated until earlier tasks have completed
  • to make your code faster
  • to ensure that the call stack maintains a LIFO (Last in, First Out) structure

Which expression evaluates to true?

  • [3] == [3]
  • 3 == ‘3’
  • 3 != ‘3’
  • 3 === ‘3’

Which of these is a valid variable name?

  • 5thItem
  • firstName
  • grand total
  • function

Which method cancels event default behavior?

  • cancel()
  • stop()
  • preventDefault()
  • prevent()

Which method do you use to attach one DOM node to another?

  • attachNode()
  • getNode()
  • querySelector()
  • appendChild()

Which statement is used to skip iteration of the loop?

  • break
  • pass
  • skip
  • continue

Which choice is valid example for an arrow function?

  • (a,b) => c
  • a, b => {return c;}
  • a, b => c
  • { a, b } => c

Which concept is defined as a template that can be used to generate different objects that share some shape and/or behavior?

  • class
  • generator function
  • map
  • proxy

How do you add a comment to JavaScript code?

  • ! This is a comment
  • # This is a comment
  • \ This is a comment
  • // This is a comment

If you attempt to call a value as a function but the value is not a function, what kind of error would you get?

  • TypeError
  • SystemError
  • SyntaxError
  • LogicError

Which method is called automatically when an object is initialized?

  • create()
  • new()
  • constructor()
  • init()

What is the result of running the statement shown?
let a = 5;
console.log(++a);

  • 4
  • 10
  • 6
  • 5

You’ve written the event listener shown below for a form button, but each time you click the button, the page reloads. Which statement would stop this from happening?
button.addEventListener(
‘click’,
function (e) {
button.className = ‘clicked’;
},
false,
);

  • e.blockReload();
  • button.preventDefault();
  • button.blockReload();
  • e.preventDefault();

Which statement represents the starting code converted to an IIFE?

  • function() { console.log(‘lorem ipsum’); }()();
  • function() { console.log(‘lorem ipsum’); }();
  • (function() { console.log(‘lorem ipsum’); })();

Which statement selects all img elements in the DOM tree?

  • Document.querySelector(‘img’)
  • Document.querySelectorAll(‘<img>’)
  • Document.querySelectorAll(‘img’)
  • Document.querySelector(‘<img>’)

Why would you choose an asynchronous structure for your code?

  • To use ES6 syntax
  • To start tasks that might take some time without blocking subsequent tasks from executing immediately
  • To ensure that parsers enforce all JavaScript syntax rules when processing your code
  • To ensure that tasks further down in your code aren’t initiated until earlier tasks have completed

What is the HTTP verb to request the contents of an existing resource?

  • DELETE
  • GET
  • PATCH
  • POST

Which event is fired on a text field within a form when a user tabs to it, or clicks or touches it?

  • focus
  • blur
  • hover
  • enter

What is the result in the console of running this code?
function logThis() {
console.log(this);
}
logThis();

  • function
  • undefined
  • Function.prototype
  • window

Which class-based component is equivalent to this function component?

✅ Which class-based lifecycle method would be called at the same time as this effect Hook?
useEffect(() => {
// do things
}, []);

  • componentWillUnmount
  • componentDidUpdate
  • render
  • componentDidMount

What is the output of this code?
var obj;
console.log(obj);

  • ReferenceError: obj is not defined
  • {}
  • undefined
  • null

What will be logged to the console?
var a = [‘dog’, ‘cat’, ‘hen’];
a[100] = ‘fox’;
console.log(a.length);

  • 4
  • 100
  • 101
  • 3

How would you use the TaxCalculator to determine the amount of tax on $50?
class TaxCalculator {
static calculate(total) {
return total * 0.05;
}
}

  • calculate(50);
  • new TaxCalculator().calculate($50);
  • TaxCalculator.calculate(50);
  • new TaxCalculator().calculate(50);

✅ What is wrong with this code?

const foo = {
  bar() {
    console.log('Hello, world!');
  },
  name: 'Albert',
  age: 26,
};
  • The function bar needs to be defined as a key/value pair.
  • Trailing commas are not allowed in JavaScript.
  •  Functions cannot be declared as properties of objects.
  • ” /> Nothing, there are no errors.

✅ What will be logged to the console?

console.log('I');
setTimeout(() => {
  console.log('love');
}, 0);
console.log('Javascript!');
  • .
I
Javascript!
love
  •  .
love
I
Javascript!
  •  The output may change with each execution of code and cannot be determined.
  •  .
I
love
Javascript!

✅ What will this code log to the console?

const foo = [1, 2, 3];
const [n] = foo;
console.log(n);
  • 1
  •  undefined
  •  NaN
  •  Nothing–this is not proper JavaScript syntax and will throw an error.

✅ How do you remove the property name from this object?

const foo = {
  name: 'Albert',
};
  •  delete name from foo;
  • ” /> delete foo.name;
  •  del foo.name;
  •  remove foo.name;

✅ What is the difference between the map() and the forEach() methods on the Array prototype?

  •  There is no difference.
  •  The forEach() method returns a single output value, whereas the map() method performs operation on each value in the array.
  • ” /> The map() methods returns a new array with a transformation applied on each item in the original array, whereas the forEach() method iterates through an array with no return value.
  •  The forEach() methods returns a new array with a transformation applied on each item in the original array, whereas the map() method iterates through an array with no return value.

✅ Which concept does this code illustrate?

function makeAdder(x) {
  return function (y) {
    return x + y;
  };
}

var addFive = makeAdder(5);
console.log(addFive(3));
  •  overloading
  •  closure
  • ” /> currying
  •  overriding

✅ Which tag pair is used in HTML to embed JavaScript?

  • ” /> <script></script>
  •  <js></js>
  •  <javascript></javascript>
  •  <code></code>

Q88. If your app receives data from a third-party API, which HTTP response header must the server specify to allow exceptions to the same-origin policy?

  •  Security-Mode
  • ” /> Access-Control-Allow-Origin
  •  Different-Origin
  •  Same-Origin

✅ What is the output of this code?

let rainForests = ['Amazon', 'Borneo', 'Cerrado', 'Congo'];
rainForests.splice(0, 2);
console.log(rainForests);
  •  ["Amazon","Borneo","Cerrado","Congo"]
  • ” /> ["Cerrado", "Congo"]
  •  ["Congo"]
  •  ["Amazon","Borneo"]

✅ Which missing line would allow you to create five variables(one,two,three,four,five) that correspond to their numerical values (1,2,3,4,5)?

const numbers = [1, 2, 3, 4, 5];
//MISSING LINE
  • ” /> const [one,two,three,four,five]=numbers
  •  const {one,two,three,four,five}=numbers
  •  const [one,two,three,four,five]=[numbers]
  •  const {one,two,three,four,five}={numbers}

✅ What will this code print?

const obj = {
  a: 1,
  b: 2,
  c: 3,
};

const obj2 = {
  ...obj,
  a: 0,
};

console.log(obj2.a, obj2.b);
  •  Nothing, it will throw an error
  • ” /> 0 2
  •  undefined 2
  •  undefined 2

✅ Which line could you add to this code to print “jaguar” to the console?

let animals = ['jaguar', 'eagle'];
//Missing Line
console.log(animals.pop()); //Prints jaguar
  •  animals.filter(e => e === "jaguar");
  • ” /> animals.reverse();
  •  animals.shift();
  • ” /> animals.pop();

Note: this question has two correct answers.

✅ What line is missing from this code?

//Missing Line
for (var i = 0; i < vowels.length; i++) {
  console.log(vowels[i]);
  //Each letter printed on a separate line as follows;
  //a
  //e
  //i
  //o
  //u
}
  •  let vowels = "aeiou".toArray();
  •  let vowels = Array.of("aeiou");
  •  let vowels = {"a", "e", "i", "o", "u"};
  • ” /> let vowels = "aeiou";

✅ What will be logged to the console?

const x = 6 % 2;
const y = x ? 'One' : 'Two';
console.log(y);
  •  undefined
  •  One
  •  true
  • Two

✅ How would you access the word It from this multidimensional array?

let matrix = [["You","Can"],["Do","It"],["!","!","!"]];

  •  matrix[1[2]]
  • ” /> matrix[1][1]
  •  matrix[1,2]
  •  matrix[1][2]

✅ What does this code do?

const animals = ['Rabbit', 'Dog', 'Cat'];
animals.unshift('Lizard');
  • ” /> It adds “Lizard” to the start of the animals array.
  •  It adds “Lizard” to the end of the animals array.
  •  It replaces “Rabbit” with “Lizard” in the animals array.
  •  It replaces “Cat” with “Lizard” in the animals array.

✅ What is the output of this code?

let x = 6 + 3 + '3';
console.log(x);
  • 93
  •  12
  •  66
  •  633

✅ Which statement can take a single expression as input and then look through a number of choices until one that matches that value is found?

  •  else
  •  when
  •  if
  • ” /> switch

✅ Which statement prints “roar” to the console?

var sound = 'grunt';
var bear = { sound: 'roar' };
function roar() {
  console.log(this.sound);
}
  •  bear.bind(roar);
  •  roar.bind(bear);
  • ” /> roar.apply(bear);
  •  bear[roar]();

✅ Which choice is a valid example of an arrow function, assuming c is defined in the outer scope?

  •  a, b => { return c; }
  •  a, b => c
  •  { a, b } => c
  • ” /> (a,b) => c

✅ Which statement correctly imports this code from some-file.js?

//some-file.js
export const printMe = (str) => console.log(str);
  •  import printMe from './some-file';
  • ” /> import { printMe } from './some-file';
  •  import default as printMe from './some-file';
  •  const printMe = import './some-file';

✅ What will be the output of this code?

const arr1 = [2, 4, 6];
const arr2 = [3, 5, 7];

console.log([...arr1, ...arr2]);
  •  [2, 3, 4, 5, 6, 7]
  •  [3,5,7,2,4,6]
  •  [3, 5, 7, 2, 4, 6]
  •  [[2, 4, 6], [3, 5, 7]]
  • ” /> [2, 4, 6, 3, 5, 7]

✅ Which method call is chained to handle a successful response returned by fetch()?

  •  done()
  • ” /> then()
  •  finally()
  •  catch()

✅ Which choice is not an array method?

  •  array.slice()
  •  array.shift()
  •  array.push()
  • ” /> array.replace()

✅ Which JavaScript loop ensures that at least a singular iteration will happen?

  • ” /> do…while
  •  forEach
  •  while
  •  for

✅ What will be logged to the console?

console.log(typeof 'blueberry');
  • ” /> string
  •  array
  •  Boolean
  •  object

✅ What is the output that is printed when the div containing the text “Click Here” is clicked?

//HTML Markup
<div id="A">
  <div id="B">
    <div id="C">Click Here</div>
  </div>
</div>
//JavaScript
document.querySelectorAll('div').forEach((e) => {
  e.onclick = (e) => console.log(e.currentTarget.id);
});
  • ” /> C B A
  •  A
  •  C
  •  A B C

✅ What will this code log to the console?

const myNumbers = [1, 2, 3, 4, 5, 6, 7];
const myFunction = (arr) => {
  return arr.map((x) => x + 3).filter((x) => x < 7);
};
console.log(myFunction(myNumbers));
  •  [4,5,6,7,8,9,10]
  •  [4,5,6,7]
  •  [1,2,3,4,5,6]
  • ” /> [4,5,6]

✅ What does this code print to the console?

let rainForestAcres = 10;
let animals = 0;

while (rainForestAcres < 13 || animals <= 2) {
  rainForestAcres++;
  animals += 2;
}

console.log(animals);
  •  2
  •  4
  • 6
  •  8

✅ Which snippet could you add to this code to print “YOU GOT THIS” to the console?

let cipherText = [...'YZOGUT QGMORTZ MTRHTILS'];
let plainText = '';

/* Missing Snippet */

console.log(plainText); //Prints YOU GOT THIS
  •  A
for (let key of cipherText.keys()) {
  plainText += key % 2 === 0 ? key : ' ';
}
  •  B
for (let [index, value] of cipherText.entries()) {
  plainText += index % 2 !== 0 ? value : '';
}
  • C
for (let [index, value] of cipherText.entries()) {
  plainText += index % 2 === 0 ? value : '';
}
  •  D
for (let value of cipherText) {
  plainText += value;
}

✅ Which Pokemon will be logged to the console?

var pokedex = ['Snorlax', 'Jigglypuff', 'Charmander', 'Squirtle'];
pokedex.pop();
console.log(pokedex.pop());
  • ” /> Charmander
  •  Jigglypuff
  •  Snorlax
  •  Squirtle

✅ Which statement can be used to select the element from the DOM containing the text “The LinkedIn Learning library has great JavaScript courses” from this markup?

<h1 class="content">LinkedIn Learning</h1>
<div class="content">
  <span class="content">The LinkedIn Learning library has great JavaScript courses!</span>
</div>
  •  document.querySelector(“div.content”)
  • ” /> document.querySelector(“span.content”)
  •  document.querySelector(“.content”)
  •  document.querySelector(“div.span”)

✅ Which value is not falsey?

  • ” /> []
  •  undefined
  •  0
  •  null

✅ What line of code causes this code segment to throw an error?

const lion = 1;
let tiger = 2;
var bear;

++lion;
bear += lion + tiger;
tiger++;
  • ” /> line 5, because lion cannot be reassigned a value
  • line 6, because the += operator cannot be used with the undefined variable bear
  • line 5, because the prefix (++) operator does not exist in JavaScript
  • line 3, because the variable bear is left undefined

✅ What will be the value of result after running this code?

const person = { name: 'Dave', age: 40, hairColor: 'blue' };
const result = Object.keys(person).map((x) => x.toUpperCase());
  •  It will throw a TypeError.
  • ["Name", "Age", "HairColor"]
  • ["DAVE", 40, "BLUE"]
  • ” /> ["NAME", "AGE", "HAIRCOLOR"]

✅ Which snippet could you insert to this code to print “swim” to the console?

let animals = ["eagle", "osprey", "salmon"];
let key = animal => animal === "salmon";

if(/* Insert Snippet Here */){
  console.log("swim");
}
  • animals.every(key)
  • animals.some(key).length === 1
  • animals.filter(key) === true
  • ” /> animals.some(key)

✅ What is the output of this code?

class RainForest {
  static minimumRainFall = 60;
}

let congo = new RainForest();
RainForest.minimumRainFall = 80;
console.log(congo.minimumRainFall);
  • ” /> undefined
  • None of these answers, as static is not a feature in Javascript.
  • 60
  • 80

✅ How can you attempt to access the property a.b on obj without throwing an error if a is undefined?

let obj = {};
  • obj?.a.b
  • ” /> obj.a?.b
  • obj[a][b]
  • obj.?a.?b

✅ What happens when you run this code?

if (true) {
  var x = 5;
  const y = 6;
  let z = 7;
}
console.log(x + y + z);
  • It will throw a ReferenceError about x.
  • It will print 18.
  • It will print undefined.
  • ” /> It will throw a ReferenceError about y.

✅ What does this code print to the console?

const x = [1, 2];
const y = [5, 7];
const z = [...x, ...y];
console.log(z);
  • ” /> [1,2,5,7]
  • [[1, 2], [5, 7]]
  • [2,7]
  • [2,1,7,5]

✅ Given this code, which statement will evaluate to false?

const a = { x: 1 };
const b = { x: 1 };
  • a['x'] === b['x']
  • a != b
  • ” /> a === b
  • a.x === b.x

✅ What will this code log to the console?

console.log(typeof 41.1);
  • Nothing. It resuults in a ReferenceError.
  • decimal
  • float
  • ” /> number

✅ What is the output of this code?

let scores = [];
scores.push(1, 2);
scores.pop();
scores.push(3, 4);
scores.pop();
score = scores.reduce((a, b) => a + b);
console.log(score);
  • 3
  • 4
  • 6
  • 7

✅ What does this code print to the console?

let bear = {
  sound: 'roar',
  roar() {
    console.log(this.sound);
  },
};

bear.sound = 'grunt';
let bearSound = bear.roar;
bearSound();
  • Nothing is printed to the console.
  • grunt
  • ” /> undefined
  • roar

✅ What is the output of this code?

var cat = { name: 'Athena' };

function swap(feline) {
  feline.name = 'Wild';
  feline = { name: 'Tabby' };
}

swap(cat);
console.log(cat.name);
  • undefined
  • Wild
  • Tabby
  • Athena

✅ What will this code output to the log?

var thing;
let func = (str = 'no arg') => {
  console.log(str);
};
func(thing);
func(null);
  • null no arg
  • no arg no arg
  • null null
  • ” /> no arg null

✅ What will this code print to the console?

const myFunc = () => {
  const a = 2;
  return () => console.log('a is ' + a);
};
const a = 1;
const test = myFunc();
test();
  • a is 1
  • a is undefined
  • It won’t print anything.
  • ” /> a is 2

✅ What will this code print to the console?

const myFunc = (num1, num2 = 2, num3 = 2) => {
  return num1 + num2 + num3;
};
let values = [1, 5];
const test = myFunc(2, ...values);
console.log(test);
  • 8
  • 6
  • 2
  • 12

✅ Which code would you use to access the Irish flag?

var flagsJSON =
  '{ "countries" : [' +
  '{ "country":"Ireland" , "flag":"🇮🇪" },' +
  '{ "country":"Serbia" , "flag":"🇷🇸" },' +
  '{ "country":"Peru" , "flag":"🇵🇪" } ]}';

var flagDatabase = JSON.parse(flagsJSON);
  • flagDatabase.countries[1].flag
  • ” /> flagDatabase.countries[0].flag
  • flagDatabase[1].flag
  • flagsJSON.countries[0].flag

✅ Which snippet allows the acresOfRainForest variable to increase?

let conservation = true;
let deforestation = false;
let acresOfRainForest = 100;
if (/* Snipped goes here */){
    ++acresOfRainForest;
}
  • ” /> conservation && !deforestation
  • !deforestation && !conservation
  • !conservation || deforestation
  • deforestation && conservation || deforestation

✅ Which of these evaluate to true?

  • Boolean(“false”)
  • Boolean(“”)
  • Boolean(0)
  • Boolean(NaN)

✅ Which method converts a JSON string to a Javascript object?

  • ” /> JSON.parse()
  • JSON.fromString();
  • JSON.stringify()
  • JSON.toObject()

✅ Which method do you use to attach one DOM mode to another?

  • attachNode()
  • ” /> appendChild()
  • querySelector()
  • getNode()

✅ How would you add a data item named animal with a value of sloth to local storage for the current domain?

  • LocalStorage.setItem(“animal”,”sloth”);
  • ” /> document.localStorage.setItem(“animal”,”sloth”);
  • localStorage.setItem({animal:”sloth”});
  • localStorage.setItem(“animal”,”sloth”);

✅ What value is printed to the console after this code execute?

let cat = Object.create({ type: 'lion' });
cat.size = 'large';

let copyCat = { ...cat };
cat.type = 'tiger';

console.log(copyCat.type, copyCat.size);
  • tiger large
  • lion undefined
  • ” /> undefined large
  • lion large

✅ What does this code print to the console?

let animals = [{ type: 'lion' }, 'tiger'];
let clones = animals.slice();

clones[0].type = 'bear';
clones[1] = 'sheep';

console.log(animals[0].type, clones[0].type);
console.log(animals[1], clones[1]);
  • ” /> bear bear tiger sheep
  • lion bear sheep sheep
  • bear bear tiger tiger
  • lion bear tiger sheep

✅ What will be the output of the following code.

a=5;
b=4;
alert(a++(+(+(+b))));
  • 18
  • 10
  • 9
  • 20

✅ What fragment could you add to this code to make it output “{“type”: “tiger”}” to the console?

let cat = { type: "tiger", size: "large" };

let json = /* Snippet here */;

console.log(json); // print {"type":"tiger"}
  • cat.toJSON("type");
  • ” /> JSON.stringify(cat, ["type"]);
  • JSON.stringify(cat);
  • JSON.stringify(cat, /type/);

✅ Which document method is not used to get a reference to a DOM node?

  • document.getNode();
  • document.getElementsByClassName();
  • ” /> document.querySelectorAll();
  • document.querySelector();

✅ Which snippet could you add to this code to print “{“type”: “tiger”}” to the console?

let cat = {type: "tiger", size: "large"};
let json= /_ Snippet Here _/;
console.log(json); //prints {"type": "tiger"}
  • ” /> JSON.sringify(cat);
  • JSON.sringify(cat, [“type”]);
  • JSON.sringify(cat, /type/);
  • cat.toJSON(“type”);

✅ In JavaScript, all objects inherit a built-in property from a ****___****.

  • node
  • instance variable
  • ” /> prototype
  • accessor
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