Salesforce Developers Certified Official Practice Test JS-Dev-101 – Oct-2026 [Q12-Q30]

QUESTION 12
Refer to the code snippet:
01 function getAvailableilityMessage(item) {
02 if (getAvailableility(item)) {
03 var msg = “Username available”;
04 }
05 return msg;
06 }
What is the return value of msg when getAvailableilityMessage(“newUserName”) is executed and getAvailableility(“newUserName”) returns false?

QUESTION 13
A developer is debugging a web server that uses Node.js The server hits a runtimeerror every third request to an important endpoint on the web server.
The developer added a break point to the start script, that is at index.js at he root of the server’s source code. The developer wants to make use of chrome DevTools to debug.
Which command can be run to access DevTools and make sure the breakdown is hit ?

QUESTION 14
A developer is leading the creation of a new browser application that will serve a single page application. The team wants to use a new web framework Minimalsit.js.The Lead developer wants to advocate for a more seasoned web framework that already has a community around it.
Which two frameworks should the lead developer advocate for?
Choose 2 answers

QUESTION 15
A developer publishes a new version of a package with new features that do not break backward compatibility. The previous version number was 1.1.3.
Following semantic versioning formats, what should the new package version number be?

QUESTION 16
Refer to the following code:
<html lang=”en”>
<body>
<button class=”secondary”>Save draft</button>
<button class=”primary”>Save and close</button>
</body>
<script>
function displaySaveMessage(event) {
console.log(‘Save message.’);
}
function displaySuccessMessage(event) {
console.log(‘Success message.’);
}
window.onload = function() {
document.querySelector(‘.secondary’)
.addEventListener(‘click’, displaySaveMessage, true);
document.querySelector(‘.primary’)
.addEventListener(‘click’, displaySuccessMessage, true);
}
</script>
</html>

QUESTION 17
Which statement accurately describes an aspect of promises?

QUESTION 18
Refer to the code below:
Let car1 = new Promise((_ , reject) =>
setTimeout(reject, 2000, “car 1 crashed in” =>
Let car2 =new Promise(resolve => setTimeout(resolve, 1500, “car 2 completed”) Let car3 =new Promise(resolve =>setTimeout(resolve, 3000, “car 3 completed”) Promise.race(( car1, car2, car3))
.then (value => (
Let result = ‘$(value) the race.’;)}
.catch(arr => {
console.log(“Race is cancelled.”, err);
});
What is the value of result when Promise.race executes?

QUESTION 19
Which statement parses successfully?

QUESTION 20
Refer to the code below:
01 let o = {
02 get js() {
03 let city1 = String(‘St. Louis’);
04 let city2 = String(‘New York’);
05
06 return {
07 firstCity: city1.toLowerCase(),
08 secondCity: city2.toLowerCase(),
09 }
10 }
11 }
What value can a developer expect when referencing o.js.secondCity?

QUESTION 21
A developer receives a comment from the Tech Lead that the code given below has error:
const monthName = ‘July’;
const year = 2019;
if(year === 2019) {
monthName =’June’;
}
Which line edit should be made to make this code run?

QUESTION 22
Refer to the code below:
01 const addBy = ?
02 const addByEight = addBy(8);
03 const sum = addByEight(50);
Which two functions can replace line 01 and return 58 to sum?

QUESTION 23
What are two unique features of functions defined with a fat arrow as compared to normal function definition?
Choose 2 answers

QUESTION 24
HTML:
<p> The current status of an Order: <span id=”status”> In Progress </span> </p> Which JavaScript statement changes ‘In Progress’ to ‘Completed’?

QUESTION 25
Refer to the code declarations below:
Which three expressions return the string JavaScript?
Choose 3 answers

QUESTION 26
Given the code below:
const delay = async delay =>{
return new Promise((resolve,reject)=>{
console.log(1);
setTimeout(resolve,deleay);
});
};
const callDelay =async ()=>{
console.log(2);
const yup = await delay(1000);
console.log(3);
}
console.log(4);
callDelay();
console.log(5);
What is logged to the console?

QUESTION 27
A developer has code that calculates a restaurant bill, but generates incorrect answers while testing the code:
function calculateBill (items ) {
let total = 0;
total += findSubTotal(items);
total += addTax(total);
total += addTip(total);
return total;
}
Which option allows the developer to step into each function execution within calculateBill?

QUESTION 28
Refer to the code below:

What is the result when the Promise in the execute function is rejected?

QUESTION 29
What are two unique features of fat-arrow functions compared to normal function definitions?

QUESTION 30
CRefer to the code below:
“`javascript
let strNumber = ‘12345’;
“`
Which code snippet shows a correct way to convert this string to an integer?