How To Prepare For Salesforce Certified JavaScript Developer I

The JavaScript Developer I exam is intended for individuals who have the knowledge, skills, and experience developing front-end and/or back-end JavaScript applications for the web stack. These skills can be applied to any framework and are not mobile or device specific.

What’s really important with this certification is that it’s the first platform agnostic exam that tests knowledge outside of Salesforce platform tools. There are also no prerequisite certifications for this exam. The official Trailhead Exam Guide can be found here.

MULTIPLE CHOICE QUESTIONS (MCQ) PATTERN.

60 multiple-choice/multiple-select questions
105 minutes allotted to complete the exam (time allows for unscored questions)
65% is the passing score

TOPICS THAT NEED TO GO THROUGH TO PASS THE CERTIFICATION.

1. Variables, Types, Collections: 23%

This part is really where you should focus on as a beginner, you might be using these concepts without even realizing it while building LWC or even Aura and VF components.

JavaScript is known to be a quirky language so be sure to get fundamentals straight at least up to a comfortable level. This is your Day One study material. Figuring these out from ground up will help you both in the exam and in your day to day job!

I’m talking about function, variable scoping, array methods, JSON methods and true and false concepts.

• Given a scenario, write code to create variables and initialize them correctly.

• Given a business requirement, utilize strings, numbers, and dates effectively.

• Given a scenario or example, demonstrate awareness of type coercion and its effects.

• Given a specific scenario, distinguish true or false evaluations

• Given a list of data, demonstrate data manipulation with arrays.

• Given a JSON response, demonstrate how to operate the JSON object.

2. Objects, Functions, and Classes: 25%

Who said JavaScript can’t be object oriented? Even though OOP can get quickly very complicated, be sure to understand the concepts like prototypes, flow control on a high-level view and be ready to dive deep on concepts like “this” keyword, block scoping, constructors and Object methods etc.

• Given a business requirement, locate the best function implementation.

• Given a business requirement, apply fundamentals of object implementation to solve the business requirement.

• Given a business requirement, apply fundamentals of class implementation to solve the business requirement.

• Given a JavaScript module, give examples of how to use the module.

• Given a JavaScript decorator, give examples of how to use the decorator.

• Given a block of code, analyze the variable scope and the execution flow.

3. Browser and Events: 17%

Your browser developer tools are your best friend in this section! Play around with DOM elements and practice using online sandboxes. I recommend understanding how to control events and browser APIs and how they can potentially work together.

• Given a business requirement, utilize Events, event handlers and propagation.

• Given a business requirement, evaluate and manipulate the DOM.

• Given a scenario, utilize the Browser Dev Tools to investigate code behavior.

• Given a scenario and requirements, utilize browser specific APIs.

4. Debugging and Error Handling: 7%

There’s more than just console.log()! Again your browser developer tool to the rescue. Learn features like debugger keyword and different ways you can display data in your log statements.

Did you know you can measure performance of functions with console methods?

• Given a scenario, handle errors properly.

• Given code to be debugged, use the console and breakpoints.

5. Asynchronous Programming: 13%

Using async/await and promises are one thing, but truly knowing the difference between them and where to use them correctly is another.

This section was difficult in my experience, especially if you’re missing out on how order of execution works in JavaScript and related concepts including Event Loop and Callstack.

• Given a scenario, apply asynchronous programming concepts.

• Given a scenario, use event loop and event monitor or determine loop outcomes.

6. Server Side JavaScript: 8%

This section is about using tools such as Node.js alongside npm. Expect both open ended questions about the features of these technologies and CLI code snippets

• Given a scenario and requirements, infer which Node.js implementation is a good solution.

• Given a scenario and requirements, infer which Node.js CLI command is a good solution.

• Know the core Node.js modules and given requirements, infer which Node.js library/framework is a good solution.

• Given a scenario and requirements, distinguish which Node.Js Package Management solution is the most fitting.

7. Testing: 8%

This section is about you guessed it, testing. Be sure to understand logical concepts of reporting a result of a test and methods like console.assert()

• With a block of code and the associated Unit Test, determine where the test is ineffective and modify it to make it more effective.

BELOW ARE THE LINKS THAT I HAVE REFERRED

I read all of the Salesforce documentation. In doing so, I recognized many of the questions within the documentation. These guides are more accessible and understandable than you might expect.