Lightning Web Components Interview Questions

LWC, or Lightning Web Component, is a programming platform introduced by Salesforce in 2018. The base computer languages used are HTML and Javascript. Business users can use it to develop applications and enhance modules and elements. With its streamlined user interface, Salesforce Lightning keeps the Salesforce platform up to date and helps clients grow.

Major companies like Adidas and Allianz rely on Salesforce Lightning in their operations to maintain the CRM. Technology keeps changing vibrantly, and so does Salesforce. The successful operation of their firm depends on Salesforce, which is used by over 150,000 significant corporations globally. And therefore, the demand for Salesforce Lightning professionals also keeps increasing. According to the Burning Glass Report, over 500k new Salesforce jobs will be created this year.

The primary requirement to get into a Salesforce job is to get certified. It is recommended to get a foundational certificate and top it up with Salesforce Lightning in-demand skill certificates. This will be your way en route to an LWC job. To succeed in the job interview will be the next step.

How to Prepare for the LWC Interview?

Candidates have a significant tendency to learn from Salesforce exam dumps while preparing for Salesforce exams. This might gain you a certificate but fail you in the interview session.

• Make notes while preparing for the Salesforce exam. These can be consulted before the interview.
• possess a thorough knowledge of the platform.
• Participate in the Salesforce Community and keep up with the newest developments.
• Even after obtaining the certificate, stay closely connected with hands-on experience through Trailblazer Superbadges and Super sets.

The interview questions get more complicated with the seniority of the role. 

Take a look at the top Lightning Web Components interview questions for 2022. Being prepared with them will put you ahead of the competition.

Fresher Level Lightning Web Components Interview Questions

If you are new to the job, you can prepare with the basic Salesforce questions and skim through the scenario-based questions. Understand the concept when you are preparing for the Salesforce Lightning interview.

1) What is Salesforce Lightning?

Ans: It is an application development platform from Salesforce which helps simplify business processes. Single-page apps can be created using Lightning for desktop and mobile.

2) What is a Lightning Framework?

Ans: It is a UI framework that helps in developing the app. Two programming models are used in Lightning Framework – Aura Components and Lightning Web Components.

3) Give the differences between Salesforce Classic and Salesforce Lightning?

Ans: Salesforce Lightning is an easier interface compared to Salesforce Classic and does not require a developer to operate. Visualforce is not always required with Lightning. Lightning is a better version as it has advanced security features.

4) You hear a lot about the Lightning Experience. What does it mean?

Ans: The latest Salesforce desktop application has been named Lightning Experience. It has been updated with the latest features, better UI, and speed.

5) Which programming models make up the Lightning Components?

Ans: Lightning Components are made up of

– Native Aura Components Model: Aura is a free UI framework technology for app development. It is powered by JavaScript and makes way for developing growth-oriented apps. Aura makes it possible to create apps without Salesforce data.

– Lightning Web Components Model: Lightning Web Components support the Web Components aspects that work efficiently in browsers. It follows W3C web standards and is specific for Salesforce-supported browsers. The framework is advanced and lightweight. Interfaces can be created without JS or a library. Thus making it simple and fast.

6) What is the Salesforce Lightning Design System(SLDS)?

Ans: The user can create Lightning Experience apps without writing a single line of CSS using Salesforce Lightning Design System. It is a CSS framework that provides the tools to develop apps according to the design language, concepts, and best practices of Lightning Experience.

7) What are component events & application events?

Ans: Component events comprise those in which child components are dismissed, and parent components are handled. It is used when data is sent from the child component to the parent component.

On the other hand, application events can be dismissed or handled by any component. It only requires that the components are part of one application and does not require any relationship between the members.

8) When is Lightning Data Service used?

Ans: Lightning data service is used when it is required to perform basic tasks like creating, editing, loading, or deleting a record without using Apex code. It handles field-level security and sharing rules and also improves UI.

9) Name the component bundles of the Lightning Platform?

Ans: The component bundles are controller, Documentation, Style, Renderer, and Helper.

10) Why is LWC better than Aura components?

Ans: The difference between LWC and Aura can also be distinguished by working on the backend.

– It requires only regular JavaScript and is, therefore, easy.

– It renders faster than aura components because LWC is built directly on a web stack.

– Being lightweight, it loads faster.

– They are more efficient and can be used in other components as it has no or minimal UI.

Lightning Web Components Interview Questions for Experienced Candidates

1) What is Scratch org?

Ans: Scratch org is a temporary Salesforce org used for testing and development. The default duration is 7 days, which can be created for up to 30 days.

2) Why is JavaScript used in Lightning Web Components?

Ans: – JavaScript determines the behavior of HTML properties.

– The import statement is used to perform operations in the module.

– The files are maintained in the ES6 module and declared locally.

– LWC core module is IWC, and JavaScript import is used to import the Lightning Element from IWC.

3) What is the role of the meta configuration file?

Ans: The metadata values of the components are specified using the meta configuration file. Any changes will show an error without a meta configuration filed.

4) What does it mean by Lighting Out?

Ans: In LWC, Lightning Out is a feature that allows the extension of the Lightning Apps. Lightning components can be accessed from any external source with the help of the Lightning Out connector. The Lightning Out JavaScript libraries enable using Lightning Components in an app across domains. The effectiveness of the Lightning Components can be improved by making it possible to utilize them in any web container, on or off the App cloud.

5) Role of Lightning: action override.

Ans: A component can be defined as an override for a standard action using the Lightning: action override feature. It overrides traditional components like New, Edit, Tab, and View.

6) What is used to set the field-level security in LWC?

Ans: Lightning: record, EditForm, Force: record data, and Lightning: record form is used to define field-level security in Salesforce Lightning Components.

7) What are Lightning pages?

Ans: Pages for Salesforce Mobile App or Lightning Experience can be created using the Lightning Page custom layout. It is a blend of Visualforce pages and page layouts. Custom Lightning components can be added to the page layout, thus providing more freedom. The structure of the Lightning page varies depending on the device and the template. The Lightning page comprises lightning components that can be placed into page regions using the Lightning App Builder.

8) What is the loading spinner in LWC?

Ans: Lightning: spinner displays an animated spinner image to denote a request in process. The loading spinner shows that data operations or a slow calculation process occur. The loading spinner can be controlled using aura: done: waiting and aura: waiting.

9) What data types can be used in Lightning components?

Ans: The basic data types, like String, Boolean, Date, Object, etc., can be used with Aura components. Aura attributes can hold S objects and move advanced data types. In Lightning Web Components, attributes do not require data types. It can hold any JavaScript data type. 

10) What are the two phases of events? How are they different?

Ans: The two phases are Bubbling and Capture. In the bubbling phase, the event travels up along with notifying the event listeners. The innermost elements run first. In the capturing phase, the reverse happens. The event travels down the DOM, and the outermost event handlers are notified first.

In Aura applications, there is a third phase called the Default phase, in which the handlers are summoned non-deterministically.

Scenario-Based Lightning Web Components Interview Questions

1) Is it possible for the existence of two users with similar profiles?

Ans: User access in the Salesforce org is defined using the profiles. Large numbers of users are assigned the same profile. It will be issued to the entire team in a similar format. If a particular user needs additional access, new permission sets are created for those users.

2) How can you add Aura components to the Visualforce page?

Ans: Component dependency can be declared by creating a reference to the Lightning app. The developer can also use <apex:includeLightning/> component or $Lightning.createComponent().

3) Creating a component for inheriting style from the parent component is required. Is it mandatory to define it in the Salesforce component?

Ans: Styles can be inherited from parents, and it is not always necessary to define them in the Salesforce component. It can be created by inheriting CSS/style from the parent component.

4) How can data be passed from one component to another unrelated component on the same page?

Ans: There are 4 different ways to achieve this.

1- Using the beta version of Lightning Messaging Service (LMS)

2- Events can be fired from the source component if they are under the same parent component. The data can be targeted using a public attribute.

3- Previously, the method of pub sub 0 components was used, which is not recommended currently.

4- Simple method of URL parameters and CurrentPageReference.

5) While reusing the code in multiple components, how can redundancy be avoided in LWC?

Ans: This can be achieved using component inheritance, JS Util components, or a static resource.