Salesforce-JavaScript-Developer Exam Questions With Explanations

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Salesforce Salesforce-JavaScript-Developer Exam Sample Questions 2025

Start practicing today and take the fast track to becoming Salesforce Salesforce-JavaScript-Developer certified.

22214 already prepared
Salesforce Spring 25 Release
221 Questions
4.9/5.0

Refer to the code below:

Which replacement for the conditional statement on line 02 allows a developer to correctly determine
that a specific element, myElement on the page had been clicked?

 

A. event.target.id =='myElement'

A.   event.target.id =='myElement'

Refer to code below:
Let first = ‘who’;
Let second = ‘what’;
Try{
Try{
Throw new error(‘Sad trombone’);
}catch (err){
First =’Why’;
}finally {
Second =’when’;
} catch (err) {
Second =’Where’;
}
What are the values for first and second once the code executes ?

A. First is Who and second is When

B. First is why and second is where

C. First is who and second is where

D. First is why and second is when

D.   First is why and second is when

A developer uses a parsed JSON string to work with user information as in the block below: 01 const userInformation ={ 02 “ id ” : “user-01”, 03 “email” : “user01@universalcontainers.demo”, 04 “age” : 25 Which two options access the email attribute in the object? Choose 2 answers

A. userInformation(“email”)

B. userInformation.get(“email”)

C. userInformation.email

D. userInformation(email)

A.   userInformation(“email”)
C.   userInformation.email

Refer to following code block:
Let array = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,];
Let output =0;
For (let num of array){
if (output >0){
Break;
}
if(num % 2 == 0){
Continue;
}
Output +=num;
What is the value of output after the code executes?

A. 16

B. 36

C. 11

D. 25

A.   16

Refer to the code below:
Const searchTest = ‘Yay! Salesforce is amazing!” ;
Let result1 = searchText.search(/sales/i);
Let result 21 = searchText.search(/sales/i);
console.log(result1);
console.log(result2);
After running this code, which result is displayed on the console?

A. > true > false B. > 5 >undefined

B. > 5 > -1

C. > 5 > 0

B.   > 5 > -1

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Salesforce JavaScript Developer I – Frequently Asked Questions

The certification validates modern JavaScript (ES6+) skills in the Salesforce ecosystem—especially with Lightning Web Components (LWC), testing, and security. It tells employers you can write maintainable, performant, and secure front-end code on the Salesforce Platform.
Typically ~60 questions (multiple-choice/multiple-select), about 100–110 minutes, and a passing score around the mid-60% range. Always confirm current numbers before you register.
You can test via online proctoring or at a Pearson VUE test center, depending on availability in your region.
The blueprint typically includes:
  • Core JavaScript: variables, functions, scope, objects, arrays
  • Asynchronous patterns: promises, async/await
  • Browser & events: propagation, default behavior
  • Error handling & debugging
  • Testing with Jest
  • LWC fundamentals: decorators, events, data access
Prioritize let/const, arrow functions, template literals, destructuring, rest/spread, modules (import/export), classes, Map/Set, promises, async/await, and array methods (map/filter/reduce).
Expect code that evaluates promise chains, microtask timing, and try/catch with async/await. You should handle rejections cleanly and avoid callback hell.
You’ll analyze outputs, fix scope/hoisting bugs, refactor to ES6+, and identify anti-patterns. Expect snippets involving events and import/export usage. Try realistic code challenges.
The emphasis is front-end JS for LWC. Know npm basics, project structure, linting, and Jest—deep Node internals are not the focus.
Understand capture/bubble, preventing defaults, custom events, and how LWC leverages standard browser patterns. Know timers, fetch, and common Web APIs.
The session typically pauses and lets you reconnect; repeated issues can end the attempt. Use a wired connection, close heavy apps, and run pre-checks.
Take timed full-length mocks, then review every explanation. Convert mistakes into flashcards and retest weak topics with targeted quizzes.
Typically you can retake after a short wait (e.g., 1 day) for the first retake and ~14 days thereafter, with a cap per release cycle. Always confirm the current policy.
Combine Trailhead, MDN, and hands-on LWC projects. Reinforce with exam-focused notes, flashcards, and mocks from salesforceking.com.
Learn @api, @wire, component composition, and data access. Practice Jest unit tests: DOM queries, events, and mocking wire adapters.
Use @salesforce/sfdx-lwc-jest, mock Apex and wire adapters, flush promises for async, and assert both DOM changes and events.
Understand try/catch for sync/async, promise rejections, and common errors (TypeError, ReferenceError). Practice with real snippets and devtools.
@wire is declarative/reactive and can leverage caching; imperative calls give you programmatic control (e.g., conditional execution). Know loading/error states and best practices for each.
High-frequency areas: array methods, prototypes/classes, closures, equality (== vs ===), truthy/falsy, and modules.
Know Lightning Web Security/Locker basics, safe DOM patterns, and XSS prevention; for performance, avoid unnecessary re-renders, cache intelligently, and manage state cleanly.
Add it to LinkedIn and your resume, publish an LWC demo repo, write a short blog post on a tricky topic you mastered, and reference client/stakeholder impact where possible.