TOP 20 Salesforce Lightning Interview Questions

In this blog post, I am going to discuss "TOP 20 Salesforce Lightning Interview Questions" for Salesforce developers.

You can also visit my other "Salesforce Lightning Interview Questions" series using the below link.

Salesforce Lightning Interview Questions.

You can also visit my  "Scenario-Based Salesforce Lightning Interview Questions" series using the below link.

Scenario Based Interview Questions

1) What is  Lightning Component Framework and What is Aura Framework?

• A lightning Component framework is a UI framework for developing single-page applications for mobile and desktop devices.

• It uses JavaScript on the client-side and Apex on the server-side. 
• The lightning Component framework makes developing apps that work on both mobile and desktop devices far simpler than many other frameworks.
• The lightning component Framework is based on Aura Framework.
• Aura Framework is designed by Salesforce which is open-source framework for creating UI components.

2) What are the different types of pages we can create using the lightning component and what are the different types of components supported in lightning pages?

  We can create different types of pages using lightning app builder as below,

1)App Page
2)Home Page
3)Record Page

Components type supported in Lightning pages:

1) Standard Components:

Standard components are Lightning components that are built by Salesforce.

2) Custom Components:

Custom components are Lightning components we create.

3) Third-Party Components on AppExchange

On AppExchange we can find packages containing components that are ready to use in the lightning app builder.

 3) What is the use of interface force:hasRecordId and How to obtain the id of the current record in lightning component?

By using force:hasRecordId interface in lightning component we can assigned the id of the current record to a lightning component. This interface adds an attribute named "recordId" to the component. The type of attribute is a string and has an 18-character Salesforce record ID.

4) What is the use of interface Lightning:actionOverride in Salesforce Lightning component?

Lightning:actionOverride  interface enables a component to be used as an override for a standard action. We can override the View, New, Edit, and Tab standard actions on most standard and all custom components. The component needs to implement the interface Lightning:actionOverride after which the component appear in the Lightning Component Bundle menu of an object action Override Properties panel.

5) What is the use of interface force:appHostable in Salesforce Lightning component?

Interface force:appHostable in component allow it to be used as a custom tab in Lightning Experience or the Salesforce mobile app.

6)  On a load of lightning component, you are required to execute some action what you will do to achieve this?

   We will use the "Init" Event which is also called the constructor of lightning component. The init event is called once the component construction is over.

   Basic Syntax:

<aura:handler  name="init" value="{!this}" action="{!c.doinit}"/>

7) you are asked to execute some action when value change is detected in one of the attribute what will you do?

  We will use the "change" Event.

  The change event is called when the value in one of the attribute changes.
  As an Example If i am having  attribute " Anyname", on change of attribute "Anyname" if i want to call javascript method i can do this as:

Syntax:

<aura:attribute name="Anyname" type="String" />
<aura:handler  name="change" value="{!v.Anyname}" action="{!c.doinit}"/>

8) What is component event in Salesforce Lightning component?

Component Events are fired by the child components and handled by the parent component.
We require parent-child relationship between two components if we want to use component event between them for communication.

9) What is application event in Salesforce Lightning component?

Application event is the event handle by any component no matter what relationship between them but they should be inside single application.

10) Explain Bound and Unbound expressions in Salesforce Lightning component?

We have two types of expression Bound expression and Unbound expression which we use to perform data binding in lightning components.

Let see two examples:

<c:ChildComp childAttributeName="{!v.parentAttributeName}" />   <!--Bound Expression-->

childAttributeName="{!v.parentAttributeName}" is a bound expression. Any change to the value of the childAttributeName attribute in child component also changes the value of parentAttributeName attribute in parent component and vice versa.

<c:ChildComp childAttributeName="{#v.parentAttributeName}" />    <!--Unbound Expression-->

childAttributeName="{#v.parentAttributeName}" is a Unbound expression. Any change to the value of the childAttributeName attribute in child component has no effect on the value of parentAttributeName attribute in parent component and vice versa.

11) What is Aura:method in Salesforce Lightning component?

We can directly call a child component controller method from the parent component controller method using Aura:method. This method is used to pass value from parent component controller to child component controller.

12)Whatis Lightning:recordForm, Lightning:recordEditForm, Lightning:recordViewForm in Salesforce Lightning component?

Lightning:recordForm

Lightning:recordViewForm

Lightning:recordEditForm


13) Explain Standard controller of lightning component (force:recordData)?

Lightning Data Service (LDS) act as the data layer for Lightning.
If we are not using LDS, every component within our app makes independent calls to the server to perform operations on a record, even if all components within our app are dealing with same record data. These are independent server calls which reduces performance.LDS identifies and eliminates requests that involve the same record data, sending a single shared data request that updates all relevant components,  it also provides a way to cache data to work offline in case the user gets disconnected, intelligently syncing the data once the connection is restored.If we have a Lightning application that creates, reads, updates, or deletes records, LDS is the best, most efficient way to do CRUD operations.

14) What is Lightning out ?

Lightning out is a feature by which we can use our lightning component inside of an external site. One of the best advantage is we can use our lightning component inside visualforce page.

15) How to use lightning component with Salesforce mobile app?

Make a tab for lightning component and include this tab in Salesforce1 mobile navigation.

16) What are the requirement to call a server side controller method from Javascript controller?

Method should be static and must be Aura enabled using @AuraEnabled.

17) What are different component bundles in Salesforce Lightning component?

A component bundle contains a component or an app and all its related resources.

When you build lightning component you deal with the following component bundles,

• Component

1.  Components contains markup for component or app.
2.  The only required resource in a bundle.
3. Each bundle contains only one component or app resource.

Ex: 

Mycomp.cmp(Sample component)

 or 

MycompApp.app(Sample app)

• Controller

Controller is used to handle client side events in components.

Ex:

Mycontroller.js

• Helper

Contains Javascript functions to handle logic.

Ex: Myhelper.js

• Style

Contains styles for the component.

Ex: Mycomp.css

• Documentation

Documentation includes description and example to demonstrate the use of component.

Ex: MyComp.auradoc

• Renderer

Contains default rendering behavior for component, We can override this by custom renderer.

Ex: MyCompRenderer.js

• SVG

It is a  custom icon resource for components that get displayed before the component name in lightning app builder or community builder.

Ex: MyComp.svg

• Design

File required for components used in Lightning App Builder, Lightning pages, Community Builder, or Flow Builder.

• App

App is used to run the component.

18) What is the difference between <lightning:input> and <ui:input> in Salesforce Lightning component?

<lightning:input> are equipped with Lightning Design System Stylling whereas <ui:input> is not equipped with Lightning Design System Stylling.

19) Explain the syntax to register the Component event?

Component:

<aura:component >

<!--Name is used to give some name say "registrationInChild" to event during registration and in the type we specify the event-->
    <aura:registerEvent name="registrationInChild" type="c:CompEvent"/> 

    <aura:attribute name="textMessage" type="String" default="Part from child comp"/>
    <lightning:button label="Click To Fire" onclick="{!c.doHandleEvent}"/>
</aura:component>

Component Event: (Name=CompEvent)

<aura:event type="COMPONENT" description="Event template" >

    <aura:attribute name="storeMessage" type="String"/>


</aura:event>

20) Explain the syntax to register the Application event? Is it compulsory to register the application event?

Component:

<aura:component >
<!--Name is used to give some name say "registrationInChild" to event during registration and in the type we specify the event-->
    <aura:registerEvent name="regInChild" type="c:AppEvent"/>
    <aura:attribute name="textMessage" type="String" default="Part from child comp"/>
    <lightning:button label="Click To Fire" onclick="{!c.doHandleEvent}"/>

</aura:component>

Application event:

<aura:event type="APPLICATION" description="Event template" >

  <aura:attribute name="storeMessage" type="String"/>
    

</aura:event>

No, It is not necessary to register the application event. It is optional. You can directly fire the event without registering.

TAGS:

salesforce interview questions,salesforce interview questions and answers,salesforce interview questions pdf,salesforce interview questions and answers,salesforce interview questions for experienced,salesforce interview questions for experienced developer,Salesforce lightning interview questions,salesforce lightning interview questions,salesforce lightning interview questions for experience,salesforce lightning interview questions and answers for experienced pdf,salesforce lightning admin interview questions,salesforce lightning scenario based interview questions,salesforce lightning mcq questions.