Hello everyone,

If you are preparing for Salesforce Lightning Web Components (LWC) interviews, one thing is very clear today. Interviews are no longer about memorizing definitions. Interviewers want to know how you think, how you build, and how you handle real project scenarios.

Earlier, questions were very direct like “What is LWC?” or “Difference between Aura and LWC?”. Today, those questions are just warm-ups. Real interviews focus on scenario-based discussions where the interviewer tries to understand:

• Have you actually worked on LWC in real projects?
• Do you know when to use which approach?
• Can you explain complex behavior in a simple, confident way?

In this guide, I’ll walk you through commonly asked scenario-based LWC interview questions with clear, practical explanations, exactly the way you should explain them in an interview. Think of this as a conversation between a senior developer and an interviewer, not textbook documentation.

Let’s get started.

1. What are lifecycle hooks in Lightning Web Components, and how do they execute when parent and child components are involved?

Lifecycle hooks in LWC are predefined methods that run automatically at different stages of a component’s life, like when it is created, inserted into the DOM, rendered, or removed.

They help us control when to execute logic, such as:

• Initializing data
• Calling Apex
• Working with DOM
• Cleaning up resources

The most important hooks are:

• constructor()
• connectedCallback()
• renderedCallback()
• disconnectedCallback()
• errorCallback()

Parent and Child Execution Order (Very Important)

When a parent and child component are involved, the execution order matters:

1. Parent constructor
2. Parent connectedCallback
3. Child constructor
4. Child connectedCallback
5. Child renderedCallback
6. Parent renderedCallback

How to explain to interviewer

“I always remember this rule: parent initializes first, but child finishes rendering first. This is important when I depend on child DOM elements or public methods.”

Example Code

Parent Component

</> JavaScript
import { LightningElement } from 'lwc';

export default class ParentCmp extends LightningElement {

    constructor() {
        super();
        console.log('Parent constructor');
    }

    connectedCallback() {
        console.log('Parent connectedCallback');
    }

    renderedCallback() {
        console.log('Parent renderedCallback');
    }
}

</> HTML
<template>
    <c-child-cmp></c-child-cmp>
</template>

Child Component

</>  JavaScript
import { LightningElement } from 'lwc';

export default class ChildCmp extends LightningElement {

    constructor() {
        super();
        console.log('Child constructor');
    }

    connectedCallback() {
        console.log('Child connectedCallback');
    }

    renderedCallback() {
        console.log('Child renderedCallback');
    }
}

2. Why do we use the constructor in an LWC, and what are its limitations compared to other lifecycle hooks?

The constructor is used to initialize default values and set up basic state for the component.

Constructor example

constructor() {
    super();
    this.message = 'Initial value';
}

What constructor is good for

• Initializing variables
• Calling super()
• Setting default values

Limitations

• You cannot access DOM elements
• You cannot call Apex
• You should not use @wire logic here

Interview-friendly explanation

“I treat the constructor like a setup phase. If I need to fetch data, access DOM, or react to page context, I always use connectedCallback or renderedCallback instead.”