LWC Lightning Web Component Interview Questions

Introduction

Salesforce Lightning interview questions are very famous. Lightening is a component-based framework created by Salesforce.com to help in app development. It is intended to help business users who are unfamiliar with this technology and often lack programming knowledge. Salesforce Lightning is a collection of tools and technologies that form the foundation of a significant upgrade to the Salesforce1 Platform (formerly known as App Cloud).

Because of its out-of-the-box component set and extensive ecosystem, many important companies, such as Cisco Systems, Adidas, Motorola Inc, and Allianz AG, use salesforce lightning to complete their corporate operations and strengthen their client interactions. As a result, certified salesforce lightning professionals have multiple work opportunities all across the world.

• Lightning components aid in the acceleration of app development and performance. Create custom components that other developers and administrators can use to customize Lightning Experience and the Salesforce mobile app.
• Lightning Admins can utilize App Builder to graphically design Lightning pages by merging off-the-shelf and custom-built Lightning components. Make your Lightning components available in the Lightning App Builder so that administrators may develop bespoke user interfaces without writing code.
• Admins can use Lightning templates and components to create communities graphically rather than writing. Make your Lightning components available in Experience Builder so that administrators may construct community pages without coding.

Today I have created a list of some lightning Interview Questions. Let’s discuss them one by one. 

27 Commonly Asked Salesforce LWC Lightning Web Components Interview Guestions

1. What are important tools included in Lightning?

The following are some of the primary tools featured with Lightning:

• The Lightning Component Framework: It is a collection of components and extensions that allows us to create reusable components, change the Salesforce1 Mobile App, and create independent apps.
• Lightning App Builder: This is a new user interface tool that allows us to create exceptionally fast apps by utilizing components given by Salesforce and platform developers.
• Lightning Process Builder: It is a user interface tool for visualizing and automating business processes.
• Lightning Schema Builder: This is another UI tool that may be used to inspect and create fields, objects, and relationships.
• Lightning Connect: It is an integration solution that allows the Force.com app to ingest data from any external source that adheres to the OData specification.

Must Read Web Developer Interview Questions

2. What do you understand about the Aura application bundle?

The Aura application bundle is made up of definitions and the resources that go with them. Aura can be defined as an interface, application, component, or event. The Aura definition bundle component is a folder that contains definition files and is located against the other metadata components. The aura definition bundle component, on the other hand, is not a single file. Instead, it is a collection of files.

3. What are the different types of events of Salesforce Lightning components?

The following are the three basic sorts of events generated by Salesforce lightning components:

• System Events: System events are triggered during the lifespan of a lightning app.
• Application Event: It is expanded across the lightning application, and any element that has enrolled for this event will receive an alert.
• Component Event: The scope of this component event is within itself or the parent component. Following that, all of the parent components will receive an alert.

4. What are the different component bundles of the lightning components?

The following is a list of the different lightning component bundles:

• Component: It defines the user interface for the lightning components.
• Controller: It contains client-side controller methods for handling events from components. It can also handle client-side events.
• Style: It is made up of component styles.
• Helper: A JavaScript function can be called from any JavaScript code in the bundle of a component. To prevent redundancy, we can define general logic in the helper and apply it later in other controller functions.
• Documentation / Document: It specifies the description, sample code, and one or more references to example components. This component bundle is used to keep track of how the component is utilized.
• Renderer: This component package includes a client-side renderer that may be used to change a component's default rendering.
• SVG: This is a custom icon resource for Lightning App Builder and Community Builder components.
• Design: It consists of the file required for Lightning Pages, Lightning App Builder, or Community Builder components.

5. What is the use of Lightning Data Service?

The following are the primary applications for Lightning Data Service:

• Lightning Data Service is utilized in our component to create, delete, update, and load records without using Apex code.
• It manages to share policies and field-level security.
• It is used to improve the user interface and the consistency of performance.
• The main advantage of using Lightning Data Service is that it allows us to perform basic functions without using Apex code.

6. What is Lightning out?

When we wish to use our component on an external site, we use the lightning out method. The most significant advantage of lightning out is the ability to use lightning components in a visual force page.

7. What are the different types of Lightning Record pages, and how can we build them?

Lightning Record pages are classified into three types:

• App page 
• Record page
• The home page

Using Lightning App Builder, we can develop or build Lightning Record pages.

8. What is the relationship between the two programming models, Native Aura Components and Lightning Web Components?

The Native Aura Components model and the Lightning, web components model can coexist as follows:

• The Lightning web components model, containing communication via events and component methods, can be included and used by the Native Aura Components model. However, this is not the case. The Lightning web components model can never be made up of Aura components; they can only be its parent.
• Using an ES Module, the code may also be shared between the Aura Components model and the Lightning web components model.

9. What do you understand by the aura definition bundle?

Aura definition bundles are a subset of bundles that contain an Aura definition and its associated resources. This could be an application, component, interface, event, or a collection of tokens. The AuraDefinitionBundle component consists of a folder containing definition files. Unlike most other metadata components, this is not a single file. It is, instead, a collection of files. Each file in a bundle represents a resource, such as applications, markup, events, code files (including controllers and helpers), documentation, and interfaces.

10. How can we add Aura components to the Visualforce page?

A developer can select any of the following suggested ways to add Aura components to the visualforce page:

• A developer can declare component dependencies by creating a reference to a Lightning app.
• A developer can use <apex:includeLightning/> component and add the Lightning component for the Visualforce JavaScript library to add aura components in the Visualforce library.
• By writing a JavaScript function, you can use the $Lightning.createComponent() to construct a page component.

11. What is the difference between <ui:input> and <lightning:input>?

The primary difference between the <ui:input> and the <lightning:input> is as follows:

• <ui:input>: It lacks the lighting design system style.
• <lightning:input>: It includes style for the lightning design system.

12. How can we get the current record id in the lightning component?

The force:hasRecordId interface must be added to a Lightning component in order to obtain the current record id. It enables the component to assign the current record's ID. If the component is utilized on a Lightning record page as an object-specific custom action or action override in Lightning Experience or the Salesforce app, the current record ID is useful. Except when utilized within Lightning Experience, and template-based communities, the Salesforce mobile app this interface has no effect.

13. What do you understand about the Lightning design system?

The Lightning Design System includes style guides and modern business UX best practices for creating pixel-perfect apps that match the Lightning Experience and Salesforce1 Mobile app's look and feel.

14. What is the difference between Visualforce and Lightning components?

Client-side-centric Lightning components are known for their dynamic, mobile-friendly nature. Visualforce components, on the other hand, are page-centric and primarily server-based.

15. What are the core principles of the Salesforce Lightning UI?

The Lightning Experience UI, which SLDS symbolizes, was created using four key design principles. The following are the details:

• Clarity: Clarity eliminates ambiguity. Allow people to observe, comprehend, and act with confidence.
• Efficiencies: Streamline and optimize workflows to make them more efficient. To assist individuals in performing better, smarter, and faster, anticipate demands intelligently.
• Consistency: Using the same answer in several situations builds familiarity and improves intuition.
• Beauty: Show respect for people's time and attention through deliberate and sophisticated crafting.

16. What is Locker service in Salesforce lightning?

The Locker Service in Salesforce Lightning is a robust security structure for the lightning components. By segregating the lightning components that belong to the namespace from the components in the different namespaces, this service improves and enhances security. By giving access to the supported APIs, the Locker service adheres to various best practices that improve the code's maintainability.

17. What is FlexiPage in Salesforce Lightning?

The metadata for a lightning page is called FlexiPage. The lightning page defines an adaptive screen with many lightning elements. It is made up of 25 different parts. FlexiPages are saved as XML files and distributed via a deployment tool or metadata API. In the API, these lightning pages are known as Flexipages.

18. What do you understand by Lightning:navigation?

The Lightning:navigation class is used to navigate to a page reference or to construct a URL from that reference. For navigation, we must define the page reference object. A page reference is a JavaScript object that refers to a page and provides a structured description of the page's type and values.

It makes it easier for us to access the following supported features:

• Lightning Component
• Object Page
• Web Page
• Knowledge Article
• Named Page
• Record Page
• Record Relationship Page
• Navigation Item Page

19. What are the various types of attributes that can be used to store data values?

The numerous sorts of attributes that can be used to store values are as follows: 

• Date 
• Datetime
• Map
• Set
• Boolean
• Decimal
• String
• Integer

20. What is the use of Lightning:recordEditForm?

The Lightning:inputField is used to create editable fields in the Lightning:recordEditForm. We can display read-only data by using the Lightning:output field.

The following features are included in the Lightning:recordEditForm:

• It shows the record edit layout for editing a specific record.
• It can also display the record in order to create the layout for a specific record.

21. Is it possible to create a Lightning Component that can be used in both mobile and desktop UI’s?

Yes, a Lightning Component that can be utilized in mobile and desktop user interfaces can be created. The Lightning Component specifies a lightning-fast experience that is responsive and ready by default, as well as Salesforce1 App compatibility. Its sensitive nature allows it to adjust to the screen's resolution. As a result, we may utilize it without any additional code on the desktop.

22. What is the purpose of the Aura: method Tag in Lightning?

The Aura: method tag is mostly used to specify the API of a component. We don't need to fire and handle a component event after using this tag, and we can immediately call the method in the component's controller on the client-side. It reduces the amount of code needed for a parent component to invoke a method on a child component that is also a parent component.

23. How can we create Lightning components for Salesforce?

The following two programming models can be used to create Salesforce Lightning components:

• Native Aura Components model
• Lightning web components model

24. What would be the most practical way to keep a programme running while deactivating a particular user?

You can put user accounts on hold to prevent them from functioning in your company while you work on deactivating them. You can update the owner of the entries he created/from any location where this user is employed until you figure out how to remove this user from the Role hierarchy. We can do this by using the FREEZE button on the user record. The user will no longer be able to log in to the programme if we hit the FREEZE button. Changing user accounts in the state does not allow you to use current user licenses in your company. To release the license, we must deactivate the user.

25. Is it possible for two users to have the same profile? Will a user with two profiles be assigned?

In a Salesforce org, profiles verify the scope of a user's access. Because the first half of the question is crucial, Yes. A single profile is distributed to a big group of people. The entire crew will be given a similar profile. The administrator will create a single Sales Profile with access to Leads, Campaigns, Opportunities, Contacts, and other corporate things. This means that a number of people have been allocated the same profile. Distribution permission sets are intended specifically for team leaders and managers who require access to additional records or objects.

26. What exactly do you mean when you say "action provider" and "value provider"?

An Action provider makes it easier to manage the component's events, actions, and handlers. A Value provider, on the other hand, allows us to use the value of a component attribute in the component JavaScript and markup controller.

27. What exactly do you mean by Scratch.org?

Scratch.org is a Salesforce org that may be expanded for testing and development. The Scratch. org can be created for up to 30 days before being deactivated. Scratch. org has a default duration of seven days.