Common interview questions and answers for LWC

Here are some common interview questions and answers for LWC (Lightning Web Components):

  • What are Lightning Web Components?
Lightning Web Components (LWC) is a programming model developed by Salesforce for building lightweight and efficient web applications on the Salesforce Lightning Platform. It uses modern web standards like JavaScript and HTML to create reusable components.

  • What are the key features of Lightning Web Components?

Lightweight and fast performance
Reusability and modularity
Enhanced security and governance
Seamless integration with other Salesforce features
Easy migration from existing Aura components
  • How is LWC different from Aura components?
LWC is a more modern and lightweight framework compared to Aura components. Some key differences include:

LWC uses a new programming model based on modern JavaScript and web standards, while Aura uses its own proprietary framework.
LWC components are built using a simplified syntax, making them easier to understand and maintain.
LWC provides better performance due to its optimized rendering and efficient event handling.
  • How do you communicate between Lightning Web Components?
Communication between Lightning Web Components can be achieved through the following methods:

Using events: Components can fire events and handle them in other components.
Using public properties: Components can expose public properties that can be accessed and modified by other components.
Using JavaScript methods: Components can invoke methods on other components using JavaScript.
  • What is the role of the Lightning Data Service in LWC?
Lightning Data Service is a standard component provided by Salesforce that allows LWC components to easily retrieve, modify, and save Salesforce data without requiring manual Apex code. It provides a declarative way to interact with Salesforce objects and fields.

  • How do you handle server-side interactions in LWC?
Server-side interactions can be handled in LWC using the Lightning Apex controller. By annotating an Apex class with the @AuraEnabled annotation, you can expose methods that can be invoked from the client-side LWC components. These methods can perform database operations, call external services, and return data to the components.

  • Can you explain the component lifecycle in LWC?
The component lifecycle in LWC consists of the following phases:

Creation: The component is initialized and its constructor is called.
Render: The component's HTML template is rendered.
Rerender: The component updates its rendering based on property changes.
RenderedCallback: The component and its child components are rendered in the DOM.
ConnectedCallback: The component is inserted into the DOM and becomes visible.
DisconnectedCallback: The component is removed from the DOM.
Error: If an error occurs during any phase, the component enters the error state.
  • How do you handle errors in LWC?
In LWC, you can handle errors by implementing error boundaries. An error boundary is a component that catches and handles errors occurring in its child components. It prevents the entire application from crashing and provides a fallback UI or error message.

  • How can you optimize performance in LWC?
To optimize performance in LWC, you can follow these best practices:

Minimize the use of complex computations and heavy data operations in the rendering cycle.
Use the @track decorator only when necessary to avoid unnecessary re-rendering.
Implement lazy loading and pagination techniques for large datasets.
Use the lightning/uiRecordApi module for efficient data retrieval and caching.
Leverage client-side caching and caching techniques like @wire to minimize server round trips.
Remember, these are just sample questions and answers. It's important to thoroughly understand the concepts and practice coding in LWC to perform well in

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