Salesforce JS Dev 101.pdf
Q: 1
A developer creates a simple webpage with an input field. When a user enters text and clicks the
button, the actual value must be displayed in the console:
HTML:
JavaScript:
01 const button = document.querySelector('button');
02 button.addEventListener('click', () => {
03 const input = document.querySelector('input');
04 console.log(input.getAttribute('value'));
05 });
When the user clicks the button, the output is always "Hello".
What needs to be done to make this code work as expected?
Options
Q: 2
Given the JavaScript below:
01 function filterDOM(searchString){
02 const parsedSearchString = searchString && searchString.toLowerCase();
03 document.querySelectorAll('.account').forEach(account => {
04
const accountName = account.innerHTML.toLowerCase();
05
account.style.display = accountName.includes(parsedSearchString) ? /* Insert code here */
06 });
07 }
Which code should replace the placeholder comment on line 05 to hide accounts that do not match
the search string?
Options
Q: 3
Given the following code:
01 counter = 0;
02 const logCounter = () => {
03 console.log(counter);
04 };
05 logCounter();
06 setTimeout(logCounter, 2100);
07 setInterval(() => {
08 counter++;
09 logCounter();
10 }, 1000);
What will be the first four numbers logged?
Options
Q: 4
A developer creates a new web server that uses Node.js. It imports a server library that uses events
and callbacks for handling server functionality. The server library is imported with require and is
made available to the code by a variable named server. The developer wants to log any issues that
the server has while booting up.
Which code logs an error at boot time with an event?
Options
Q: 5
Refer to the code below:
01 x = 3.14;
02
03 function myFunction() {
04 'use strict';
05 y = x;
06 }
07
08 z = x;
09 myFunction();
Considering the implications of 'use strict' on line 04, which three statements describe the execution
of the code?
Options
Q: 6
A developer wants to use a module called DatePrettyPrint.
This module exports one default function called printDate().
How can the developer import and use printDate()?
Options
Q: 7
A page loads 50+
elements, all ads.
Developer wants to quickly and temporarily remove them.
Options:
Options
Q: 8
Refer to the code:
01 let car1 = new Promise((_, reject) =>
02 setTimeout(reject, 2000, "Car 1 crashed in"));
03 let car2 = new Promise(resolve =>
04 setTimeout(resolve, 1500, "Car 2 completed"));
05 let car3 = new Promise(resolve =>
06 setTimeout(resolve, 3000, "Car 3 completed"));
07
08 Promise.race([car1, car2, car3])
09 .then(value => {
10
let result = '$(value) the race.';
11 })
12 .catch(err => {
13
console.log("Race is cancelled.", err);
14 });
What is the value of result when Promise.race executes?
Options
Q: 9
Refer to the code below:
01 let total = 10;
02 const interval = setInterval(() => {
03 total++;
04 clearInterval(interval);
05 total++;
06 }, 0);
07 total++;
08 console.log(total);
Considering that JavaScript is single-threaded, what is the output of line 08 after the code executes?
Options
Q: 10
Given the following code:
01 let x = null;
02 console.log(typeof x);
What is the output of line 02?
Options
Question 1 of 10
