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JavaScript developer certificate: How to get it

We take you on a journey to become a certified Salesforce JavaScript developer.

Many of our developers at COViS earned her Salesforce JavaScript developer certificate. We would like to share a impression of the challenges associated with this certification and encourage you to take this exam too. In case you are not too familiar with Salesforce yet – don't stop reading! This could be your way into the Salesforce ecosystem.

Salesforce Trailhead: where to start?

First, the JavaScript developer certificate consists of two parts. One is the multiple-choice exam about the various strengths and quirks of JavaScript that you have to register for via Webassessor. The other is Trailhead superbadge Lightning Web Components Specialist. The order in which you complete those two is your choice. Personally, we would suggest to complete the superbadge first – this way, you gain some more practical JavaScript experience.

Tackling the LWC specialist superbadge

If you've completed some superbadges on Trailhead already, you know what it roughly entails: it is a practical real-world scenario in which a customer is in need of certain functionality on the Salesforce platform. You are supposed to provide this functionality step by step by coding the required LWCs (Lightning Web Components) on a Salesforce org (a Trailhead playground you will be able to create from the superbadge page). For every component you will be provided with code snippets that contain the scaffolding, including method signatures that are required for the automatic code checks. So basically, you only have to fill out given methods or HTML tags with some code that implements the given use cases. Sounds easy, but let me give you some more details in a bit.

Step by step: complete the Trailhead Salesforce modules first

Before you can tackle the superbadge, there are four smaller Trailhead modules that you need to complete first as indicated at the top of the LWC superbadge page. With each one you will gain some basic experience with developing LWCs on the Salesforce platform. All you need is a Trailhead account. So grab a coffee and get going!

14 hours for challenges and solution

Now that you've finished the prerequisites and the prework from the superbadge you'll notice that one and a half dozen sub-challenges are required for the superbadge. Quite many, which will take their time. Trailhead's time estimation of 14 hours may be fitting for you, but may as well be too little. It strongly depends on how quickly your functional solution matches the expected formal solution. This means that the code check may fail even though functionally, your component fully implements the described use case. This was a big challenge. Sometime you might think your components are working as expected, but still the code check says otherwise.

What you should observe by taking the test

There certainly is a thin line between success and failure which can cost you time. If you want to be efficient, I'd suggest you proceed as follows:

  • Follow the instructions in the text closely and use the code snippets provided as starting points.

  • Pay attention to the comments in the code snippets - they give you some additional hints.

  • Look closely at dependencies between components. The order in which the requirements are presented is not necessarily the order in which you need to compose and deploy the corresponding components (also see the help page provided).

  • Whereas most components you'll create from scratch, there are some existing code artifacts from the unlocked package. You'll need to retrieve these and change slightly, so make sure that you are familiar with the SFDX commands for retrieving and deploying artifacts.

  • Don't try to do more than is requested. Additional, unnecessary code lines may even cause a failed code check.

  • The last two challenges in the superbadge are quizzes with ten questions each. You'll have to answer correctly in order to pass, but don't worry, you can try as often as you want. You'll merely get points subtracted from your total if you don't get it right the first time. Use the LWC developer guide for looking up technical information on the contents covered.

  • In case a code check for your component fails, carefully re-check your code against the instructions first. If everything is complete and works as expected, try making minor refactoring changes (e.g. using constants instead of string literals for toast messages, splitting one-liners into several lines). If that still doesn't help, try googling the error message and see how others have managed to succeed.

Obviously, googling should be the last step as you certainly want to gain proper coding experience with LWCs. Mistakes are part of the game and make you realize how and why something works!

Tackling in smaller bits: update and install the newest version

In case you are tackling the superbadge in smaller bits over several weeks, make sure to compare the version of the unlocked package, that you installed in your org against the newest version provided in the superbadge from time to time. You might need to install the newest version to be up-to-date. Beware that the given code snippets may also change slightly. At least this was the case for me.

Preparing for the Salesforce JavaScript developer certificate

So, you finished the LWC specialist superbadge – congrats! Now you'll want to prepare for the multiple-choice exam for your certificate for JavaScript. Preparation is the key to success, even if you are already very familiar with JavaScript development. The exam can be tricky as it confronts you with code snippets, some of which you wouldn't even consider writing yourself. Also, there may be questions on aspects of JavaScript that you have never thought or even heard of before. Yet another good reason is that the more familiar you are with the type of questions asked, the less time you will need to get adjusted to the questions during the exam. Now that I've convinced you to prepare for it, let us give you some advice for preparation.

How to prepare for the JavaScript developer exam

These advices will help you to prepare for the JavaScript developer certificate.

Read the official JavaScript exam guide

As a first step, you should take a look at the official exam guide. In fact, pretty much all you need to know is included in the guide via links to respective Trailhead modules, the Mozilla documentation and other informative websites about JavaScript. The Trailhead modules are a fun way to start preparing, but the JavaScript documentation… I understand if you don't want to go through all the pages of documentation. This can become boring quickly and is also time-consuming. But to be informed is the first step to start the exam, so you should have at least a rough overview.

Code snippets for testing your knowledge

For testing your knowledge of JavaScript based on code snippets I recommend you this well-thought-out compilation of JavaScript questions with their answers and short explanations. Over 150 questions give you quite a bit of groundwork for the exam as they'll cover many aspects of JavaScript. At times those questions will make you raise your eyebrows. Try the code snippets in a JavaScript playground to verify and play around with them some more. Don't expect these questions to be representative of the exam, though. In the exam you'll have to expect a bit more text to read and various kinds of questioning referring to some code.

Practicing with representative questions

If you're interested in more representative practice questions, I warmly recommend you Focus on Force with its practice exams for the JavaScript Developer I. This course costs $19 and requires you to register – but it's worth it. You'll get over 150 exam-like questions that are categorized by exam sections and two full practice exams à 60 questions. This makes it easy to test your knowledge section-wise for a better identification of where you have the biggest gaps to close. For each question you'll get a short explanation of why an answer is correct or wrong and – even more importantly - suitable reference links to an official JavaScript documentation. After you're done with that, you'll certainly be prepared quite well for the exam.

JavaScript exam example: this is how the questions look like

Based on the preparations for JavaScript developer certificate, we've come up with an example to illustrate one potential type of exam questions that you can see on the right. It is kept simple and short with respect to the question and code snippet, but you'll likely come across some code snippets of the like in the exam. Some variables are declared and initialized in some function (or class) and an output is generated with these variables. So what do you think the answer is?

What gets logged in the browser console when executing this immediately invoked function expression? Choose one answer.

  • A) 'Hello' & 'World' & 'Hello' & 'World'

  • B) undefined & undefined & 'Hello' & 'World'

  • C) 'Hello' & undefined & 'Hello' & 'World'

  • D) undefined & ReferenceError

Well, the code highlighting gives it away a bit already – it is not A, obviously. But it's not B either – this question particularly addresses the differences in behaviour between var and let. So is it C? No, it's a trap! ... It's D: You need to know the concept of hoisting in JavaScript for this. You also need to know about the temporal dead zone of let-declared variables: You may not reference them before their initialization – in contrast to var-declared variables.

Final tips for the JavaScript developer exam

That's basically all there is to it. So you are ready to start the exam. Here are some final tips to achieve the JavaScript developer certificate:

  • You can expect questions with an introductory text (e.g. starting with "A developer at Universal Container has prepared some code for…") and a code snippet. Try to skim the text quickly and get a look at the code snippet before thinking too much about the details in the text.

  • Sometimes the texts and code snippets seem more complex than the actual question and answers are. Don't get irritated by long texts!

  • The number of answers is usually between four and five and you either have to choose one answer or multiple (how many is indicated every time).

  • When slightly varying code lines are offered as answers, you can often quickly exclude one or two of those e.g. by comparing their syntax to one another.

  • The code snippets vary in their complexity, sometimes it's simple enough so that you won't have to overthink it when reading it, while at other times you should be careful not to fall into traps.

  • Take your time and don't stress if you can't come up with the correct answer right away. There will most likely be other questions that you can finish more quickly.

  • Part of the exam consists of pure knowledge about Web APIs, Node.js libraries and CLI commands. It may be helpful enough to go through some of those when preparing with the Focus on Force practice exams. Knowing every last library, API method and command is not worth the time. It's much more important to have a solid understanding of JavaScript's workings while having a rough idea of the different API's, libraries etc.

Get the party started! Good luck to you!

Great, you're ready now. So get your Webassessor account and register for the exam!

Helpful References

Get started with Trailhead:

Trailhead exam guide:

LWC specialist superbadge:

LWC specialist help:


Linking your Webassessor and your Trailhead account:

JavaScript questions by Lydia Hallie on GitHub:

Focus on Force practice exams and study guides:

LWC developer guides:

Lightning design system:

SFDX command reference:

SFDX setup:

JS Fiddle:

Salesforce Developer Blog:

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