LinkedIn JavaScript Assessment

LinkedIn Assessments - JavaScript 2019-2021

Overview

Answer 15-20 timed, multiple-choice questions

• ~15 minutes duration
• 70th percentile required to pass and get a badge
• Retry in 3 months if you don’t pass

Q1. 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.preventDefault();

Q2. Which statement references the DOM node created by the code shown?

 <p class="pull">Lorem Ipsum </p>

• document.querySelector(“.pull”);

Q3. Which statement is the correct way to create a variable called rate and assign it the value 100?

let rate = 100;

Q4. When would the final statement in the code shown be logged to the console?

let modal = document.querySelector('#results');
setTimeout(function() {
  modal.classList.remove('hidden');
}, 10000);
console.log('Results shown');

• Immediately

Q5. Which statement creates a new object using the Person constructor?

• var student = new Person();

Q6. When would you use a conditional statement?

• When you want your code to choose between multiple options.

Q7. How is forEach statement different from a for statement?

• A for statement is generic but a forEach statement can be used only with an array.

Q8. Review the code below. Which statement calls the addTax function and passes 50 as the argument?

addTax(50);

Q9. 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);

• ‘snow’

Q10. How does a function create a closure?

• It returns a reference to a variable in its parent scope.

Q11. What is the result in the console of running this code?

"use strict";
function logThis() {
  this.desc="logger";
  console.log(this);
}
new logThis();

• logThis { desc: ‘logger’ }

Q12. What is the result of running this statement?

console.log(typeof(42));

• ‘Number’

Q13. Which operator returns true if the two compared values are not equal?

• !==

Q14. Which statement is the correct way to create a variable called rate and assign it the value 100?

let rate = 100;

Q15. Which statement creates a new object using the Person constructor?

var student = new Person();

Q16. How would you reference the text ‘avenue’ in the code shown?

roadTypes[2]

Q17. Which property references the DOM object that dispatched an event?

• target

Q18. Which method converts JSON data to a JavaScript object?

JSON.parse()

Q19. When would you use a conditional statement?

• When you want your code to choose between multiple options

Q20. What would be the result in the console of running this code?

for(var i=0; i<5; i++){ 
  console.log(i); 
}

• 01234

Q21. What is the name of a function whose execution can be suspended and resumed at a later point?

• Generator

Q22. 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(j) {setTimeout(function() {console.log(j);}, j * 1000);})(i)};

Q23. Which statement creates a new function called discountPrice?

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

Q24. You need to match a time value such as 12:00:32. Which of the following regular expressions would work for your code?

• /\d\d:\d\d:\d\d/

Q25. How many prototype objects are in the chain for the following array?

let arr = [];

• 2

Q26. Which of the following is not a unary operator?

• instanceof

Q27. What type of scope does the end variable have in the code shown?

var start = 1;
if (start === 1) {
  let end = 2;
}

• block

Q28. What will the value of y be in this code:

const x = 6 % 2;
const y = x ? 'One': 'Two';

• Two

Q29. Which keyword is used to create an error?

• throw

Q30. What’s one difference between the async and defer attributes of the HTML script tag?

• The defer attribute will asynchronously load the scripts in order

Q31. 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.

Q32. Which statement references the DOM node created by the code shown?

<p class="pull">lorem ipsum</p>

• document.querySelector('.pull');

Q33. What value does the code return?

let answer = true;
if (answer === false) {
  return 0;
} else {
  return 10;
}

• 10

Q34. What is the result in the console of running the code shown?

var start = 1;
function setEnd() {
  var end = 10;
}
setEnd();
console.log(end);

• ReferenceError

Q35. What will this code log in the console?

function sayHello() {
  console.log("hello");
}
console.log(sayHello.prototype);

• undefined

Q36. Which collection object allows unique value to be inserted only once?

• Set

Q37. 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.

Q38. For the following class, how do you geet value of 42 from x?

class X{
    get Y(){return 42;}
}
var x = new X();

• x.Y

Q39. What is the result?

sum(10,20);
diff(10,20);
function sum(x,y){
  return x+y;
}
let diff = function(x,y){
  return x-y;
}

• ReferenceError

Q40. Which variable is an implicit parameter for every function in JavaScript?

• Arguments

Q41. What does the following expression evaluate to?

[] == [];

• False

Q42. Which statement is true about Functional Programming?

• Side effects are not allowed.

Q43. Which choice is not a unary operator?

• instanceof

Q44. What will the value of y be in this code:

const x = 6 % 2;
const y = x ? 'One' : 'Two';

• Two

Q45. What value does this code return?

let answer = true;
if (answer === false) {
  return 0;
} else {
  return 10;
}

• 10

Q46. What two values will this code print?

function printA() {
  console.log(answer);
  var answer = 1;
}
printA();
printA();

• undefined then undefined

Q47. Why might you choose to make your code asynchronous?

• to start tasks that might take some time without blocking subsequent tasks from executing immediately