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Salesforce JavaScript-Developer-I Exam Overview:
| Certification Vendor: | Salesforce |
|---|---|
| Exam Name: | Salesforce Certified JavaScript Developer I Exam |
| Exam Number: | JS-Dev-101 / JavaScript-Developer-I |
| Exam Duration: | 105 minutes |
| Exam Price: | USD 200 (+ applicable taxes) |
| Related Certifications: | Salesforce Certified Lightning Web Components Specialist Salesforce Certified Platform Developer I |
| Real Exam Qty: | 60 scored + up to 5 unscored |
| Certificate Validity Period: | No expiration; requires regular maintenance via Trailhead modules |
| Exam Format: | Multiple-select, Multiple-choice |
| Available Languages: | English, Japanese |
| Passing Score: | 65% |
| Recommended Training: | Salesforce JavaScript Developer I Certification Prep |
| Exam Registration: | Salesforce Certification Registration |
| Sample Questions: |  |
| Exam Way: | Online proctored or onsite at authorized testing centers |
| Pre Condition: | No formal prerequisites; 1–2 years of JavaScript development experience recommended |
| Official Syllabus URL: | https://trailhead.salesforce.com/credentials/javascript-developer-i |
Salesforce JavaScript-Developer-I Exam Syllabus Topics:
| Section | Weight | Objectives |
|---|---|---|
| Testing | 7% | - Testing frameworks and assertions - Test doubles and mocks - Unit testing concepts - Code coverage and best practices |
| Asynchronous Programming | 13% | - Fetch API and HTTP requests - Async/await syntax - Callbacks and callback hell - Promises and chaining - Event loop and micro/macro tasks |
| Server-Side JavaScript | 8% | - Command-line tools and scripts - Module system and require/import - Core Node.js modules - Node.js fundamentals and runtime |
| Browsers and Events | 17% | - Window and document object properties - Browser APIs and Web Storage - Script loading and execution order - Event handling, propagation, and delegation - Document Object Model (DOM) manipulation |
| Variables, Types, and Collections | 23% | - Variable declaration and initialization - Type coercion and conversion rules - JSON parsing and usage - Working with strings, numbers, dates, and booleans - Truthy and falsy values - Array methods and data manipulation |
| Objects, Functions, and Classes | 25% | - Object creation, properties, and methods - Closures and execution context - Decorators and advanced function patterns - Class syntax, inheritance, and prototypes - Function definitions, parameters, and scope - Modules and imports/exports |
| Debugging and Error Handling | 7% | - Debugging tools and breakpoints - Console methods and logging - Defensive programming practices - Error types and exception handling |
JavaScript-Developer-I Exam Facts: What to Know Before You Commit
Salesforce recommends the following official training resources:
Choose the format that fits your schedule, then reinforce it with regular question practice.
The latest exam information lists 60 scored + up to 5 unscored questions for the JavaScript-Developer-I exam, to be completed within 105 minutes minutes. Knowing the format cold is half the battle — timed practice handles the other half.
These are the core domains of the Salesforce Certified JavaScript Developer (JS-Dev-101) blueprint:
- Testing (7%)
- Server-Side JavaScript (8%)
- Objects, Functions, and Classes (25%)
The remaining domains appear in the full official outline, all of which our bank addresses.
Salesforce sets the following prerequisites for the Salesforce Certified JavaScript Developer (JS-Dev-101): No formal prerequisites; 1–2 years of JavaScript development experience recommended.
Check the current requirements on the official certification page before scheduling.
Validity is maintained, not assumed. Our dedicated IT team checks the system and pushes new versions to the site continuously, so the JavaScript-Developer-I bank on sale is always the latest — with expert-verified answers across the Salesforce Certified JavaScript Developer (JS-Dev-101) objectives. You can also pick the format that fits your devices: an easy-to-read PDF, a Windows PC test engine, or a browser-based online engine for Windows, Mac, Android, and iOS. Questions? Support replies to instant messages and emails within two hours.
Upon successful payment, the complete materials are available immediately: a download link on screen and an automatic email to your mailbox within about a minute. If nothing arrives within two hours, check spam and contact support. Every purchase carries a 365-day service warranty — you can download the latest valid version free whenever it is released, no matter when you bought — and a 50% renewal discount follows when the period ends.
Use the official registration channels below:
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Yes, we keep our promises — in writing. If you fail the corresponding exam within 60 days of purchase, email us a scanned copy of your enrollment slip and your official Score Report PDF within two days of the exam date; we process verified refunds in full within seven days. The exclusions are plain: exams taken within three days of purchase, candidate names that do not match the payer, and free or expired products. If you prefer, we will exchange your product for two others of equal value at no charge.
As of the latest information, the JavaScript-Developer-I exam's passing score is 65% and the registration fee is USD 200 (+ applicable taxes). Salesforce can adjust either figure, so verify both on the official site before you book.
Salesforce Certified JavaScript Developer (JS-Dev-101) Sample Questions:
A developer needs to debug a Node.js web server because a runtime error keeps occurring at one of the endpoints.
The developer wants to test the endpoint on a local machine and make the request against a local server to look at the behavior. In the source code, the server.js file will start the server. The developer wants to debug the Node.js server only using the terminal.
Which command can the developer use to open the CLI debugger in their current terminal window?
(With corrected typing errors: node_inspect # node inspect, node_start_inspect # node start inspect.)
- A. node -i server.js
- B. node inspect server.js
- C. node start inspect server.js
- D. node server.js --inspect
Correct Answer: B 🗳️
A developer publishes a new version of a package with bug fixes but no breaking changes. The old version number was 2.1.1.
What should the new package version number be based on semantic versioning?
- A. 3.1.1
- B. 2.2.0
- C. 2.2.1
- D. 2.1.2
Correct Answer: D 🗳️
Explanation: Only visible for TestInsides members. You can sign-up / login (it's free).
A developer has a fizzbuzz function that, when passed in a number, returns the following:
* ' fizz ' if the number is divisible by 3.
* ' buzz ' if the number is divisible by 5.
* ' fizzbuzz ' if the number is divisible by both 3 and 5.
* Empty string ' ' if the number is divisible by neither 3 nor 5.
Which two test cases properly test scenarios for the fizzbuzz function?
- A. let res = fizzbuzz(3);
console.assert(res === ' ' ); - B. let res = fizzbuzz(true);
console.assert(res === ' ' ); - C. let res = fizzbuzz(5);
console.assert(res === ' fizz ' ); - D. let res = fizzbuzz(15);
console.assert(res === ' fizzbuzz ' );
Correct Answer: B,D 🗳️
Explanation: Only visible for TestInsides members. You can sign-up / login (it's free).
Original code:
01 let requestPromise = client.getRequest;
03 requestPromise().then((response) = > {
04 handleResponse(response);
05 });
The developer wants to gracefully handle errors from a Promise-based GET request.
Which code modification is correct?
- A. Add .catch to the Promise chain
- B. Use finally handler for errors
- C. (duplicate of A)
- D. try/catch around requestPromise().then(...)
Correct Answer: A 🗳️
Explanation: Only visible for TestInsides members. You can sign-up / login (it's free).
A developer wants to use a module named universalContainerslib and then call functions from it. How should a developer import every function from the module and then call the functions foo and bar?
- A. import {foo, bar} from ' /path/universalContainerslib.js ' ;
foo();
bar(); - B. import all from ' /path/universalContainerslib.js ' ;
universalContainerslib.foo();
universalContainerslib.bar(); - C. import * as lib from ' /path/universalContainerslib.js ' ;
lib.foo();
lib.bar(); - D. import * from ' /path/universalContainerslib.js ' ;
universalContainerslib.foo();
universalContainerslib.bar();
Correct Answer: C 🗳️
Explanation: Only visible for TestInsides members. You can sign-up / login (it's free).
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