In this article, we are going to learn about one of the most interesting topics in the software industry. LWC is also known as Lightning Web Component, introduced to the global market by Salesforce in 2018. It is a programming paradigm that is used to develop Salesforce lightning components. LWC is built using basic HTML and JavaScript. It strengthens custom elements, modules, and so on. Due to its craze in the market, there is a large need for LWC Salesforce developers. It is recommended to go through this set of LWC interview questions and answers thoroughly before attending an interview.

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40+ LWC Interview Questions and Answers

1. Expand LWC.

The term stands for Lightning Web Components.

2. How is LWC different from Aura?

LWC-based lightning components are built using web stack tools, whereas aura-based lightning components are built using HTML5 and JavaScript tools.

3. Which company introduced LWC to the worldwide software market?

Salesforce introduced LWC to the worldwide software market.

4. What do you mean by Salesforce Lightning?

Salesforce Lightning is a component-based framework, for Salesforce App development. Its main objective is to simplify the process of development for those who do not have proper experience in programming.

5. Expand LCF.

The term LCF stands for Lightning Component Framework.

6. What is the use of a Lightning Component Framework?

In general terms, a Lightning Component Framework is a user-interface framework that is used to develop dynamic web applications for both mobile and desktop users.

7. In how many ways can lightning components be made?

There are two (2) ways in which lightning components can be made. They are 

  1. Aura Components model, and 
  2. Lightning Web Components model.

8. Mention some of the components of Salesforce Lightning.

Here are some of the components of Salesforce Lightning. They are

  1. Lightning Exchange
  2. Lightning Component Framework
  3. Visual Building Tools
  4. Lightning Experience and
  5. Lightning Design System

9. Mention some of the types of events of Salesforce Lightning components.

There are three different types of events of Salesforce Lightning components. They are

  1. Application Event 
  2. System Event and 
  3. Component Event

10. What is LWC?

The term LWC stands for Lightning Web Components. It is used to develop custom HTML elements with the help of JavaScript and HTML tools. 

11. Do you think Aura Web Components and Lightning Web Components can coexist together?

Yes, both Aura Lightning components and Lightning Web Components can coexist together.

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12. What does a component bundle contain?

Here are some of the component bundles of a lightning component:

  1. Style
  2. Renderer
  3. Documentation
  4. Helper and 
  5. Controller

13. What is the use of Visual Building tools?

These Visual Building tools provide drag-and-drop features making app development quicker and easier.

14. What are the different Lightning page types?

There are different types of Lightning page types available. Some of them are presented here:

  1. Embedded Service Page
  2. Home Page
  3. App Page and 
  4. Record Page

15. What are the advantages of using Lightning Component Framework?

Here are some of the benefits of using the Lightning Component Framework.

  1. It provides out-of-the-box components
  2. Rich Custom Component Ecosystem
  3. Fast Development
  4. Device-aware and Cross Browser Compatibility

16. List out the sequence of Application event propagation.

Here is the sequence of Application event propagation.

  1. Event fired
  2. Capture Phase
  3. Bubble Phase and 
  4. Default Phase

17. Describe the file structure of Lightning Web Components.

Here is the file structure of Lightning Web Components.

  1. myComponent.html
  2. myComponent.js
  3. myComponent.js-meta.xml
  4. myComponent.css
  5. myComponent.svg

18. What are the rules to be followed while naming files?

Here are some of the rules that are to be followed while naming a file. They are

  1. The names of the file must begin with a lowercase letter.
  2. The name of the file must contain only alphanumeric or underscore characters.
  3. The name of the file must be unique in the namespace.
  4. The name of the file must not have whitespaces in it.
  5. The name of the file should not end with an underscore. 
  6. The name of the file should not contain two consecutive underscore      characters.
  7. The name of the file should not contain a hyphen. 

19. How to iterate through the list in LWC?

There are two different ways to iterate through the list in LWC. 

  1. Use for: each
  2. Iterator

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20. Expand SLDS.

The term SLDS stands for Salesforce Lightning Design System.

21. What is the use of the Salesforce Lightning Design System?

Salesforce Lightning Design System is used to develop web applications with great lightning experience, without writing a single line of code in CSS3.

22. Is there any possibility of having multiple wire methods in Lightning Web Component?

Yes, there is a possibility of having more than two wire methods in Lightning Web Components.

23. What is renderedCallback() in Lightning Web Components?

renderedCallback() is a function in Lightning Web Components, that is used to carry out a logic once a component has completed the rendering phase.

24. Explain more about Salesforce Lightning Design System.

The Salesforce Lightning Design System is a CSS3 framework that aids the developers to create a great lightning experience using the font, color palettes, icons, and so on.

25. What is the use of @wire in LWC?

Wiring is a useful property in Lightning Web Components. When the wiring service provisions data, then rendering of the component occurs. It is used to specify a wire adapter.

26. List out the tools present in Salesforce Lightning.

Here are some of the tools present in Salesforce Lightning.

  1. Lightning Component Framework
  2. Lightning Connect
  3. Lightning App Builder
  4. Lightning Schema Builder and 
  5. Lightning Process Builder

27. What is Lightning Process Builder?

Lightning Process Builder is one of the tools present in Salesforce Lightning. It is a user-interface tool used to create visualizations and automate processes. 

28. Expand SFDX.

The term SFDX stands for Salesforce Developer Experience.

29. What is the use of Salesforce Developer Experience?

This Salesforce Developer Experience is also known as SFDX or just DX. It is a set of tools that are used to improve the developer’s experience of working upon the platform.

30. Which method is called when every component is connected or when the reactive properties have changed?

The @wire method is called automatically when every component is connected or when the reactive properties are changed.

31. State whether the given statement is true or false?

Statement: The Data returned by the imperative apex methods is immutable.

False, the imperative apex method returns the data which is mutable.

32.  State whether the given statement is true or false?

Statement: Lightning Web Components work faster than Aura components.

True, the Lightning Web Components work faster than Aura components. 

33. Why does LWC work faster than Aura components?

Normally, the lightning web components work faster than aura components. This is because due to the absence of an abstraction layer, LWC is a lightweight framework built using web stack tools such as HTML and JavaScript. 

34. How do Lightning Web components communicate with Aura components?

There is a possibility that Aura components communicate with Lightning Web Components with the help of Public APIs and Events. 

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35. State whether the given statement is true or false?

Statement: Lightning Web Components can be embedded within Aura Components.

True, Lightning Web Components can be embedded within Aura Components whereas the reverse cannot happen. 

36. Mention some disadvantages of Lighting Web Components.

Here are some of the disadvantages of using Lightning Web Components. They are

  1. It does not support the LEX console.
  2. LWC does not provide two-way binding
  3. LWC restricts the usage of Email templates and so on.

FAQs

1. What are the best practices in LWC?

Some of the best practices in LWC are mentioned here. They are 

  1. Use a dispatcher component to listen and relay events
  2. Segregate business-level events and low-level events
  3. Whenever possible, clear the cache data
  4. Use helper methods and so on

2. What is the difference between Aura and LWC?

There is a particular difference between Aura and LWC. The LWC-based lightning component is built using web stack tools, whereas the aura-based lightning components are built using HTML5 and JavaScript tools. 

3. How many components are there in LWC?

The LWC has mainly three components. They are LWC Framework, Base 

Lightning Components, and Salesforce Bindings.

4. What is the purpose of LWC?

LWC is a programming model developed by Salesforce and its main purpose is to help developers create reusable HTML tags for web pages and applications.

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Conclusion

In this article, we discussed some of the most important LWC interview questions and their answers. We hope that this article helps you in preparing for the LWC interview questions and answers confidently. If you are looking to enhance your LWC skills further, we would recommend you to take up Simplilearn’s Post Graduate Program in Full Stack Web Development in collaboration with Caltech CTME. This course can be a great way to power ahead your career in software development.

If you have any questions or doubts, feel free to post them in the comments section below. Our team will review them and get back to you with solutions at the earliest.

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