In Salesforce Lightning Web Components (LWC), lifecycle hooks are methods that allow developers to hook into the lifecycle of a component. These hooks enable you to perform actions at specific stages of a component's lifecycle, such as when the component is created, rendered, inserted into the DOM, or removed from the DOM. Here are the available lifecycle hooks in LWC along with explanations and code samples:
1. **constructor()**: This is the first lifecycle hook called when a component is created. It is used for initializing component state or setting up i
nitial values.
nitial values.
```javascript
import { LightningElement } from 'lwc';
export default class MyComponent extends LightningElement {
constructor() {
super();
// Initialize state or perform setup tasks
}
}
```
2. **connectedCallback()**: This lifecycle hook is called when the component is inserted into the DOM. It's commonly used for setting up event listeners or performing one-time initialization tasks.
```javascript
import { LightningElement } from 'lwc';
export default class MyComponent extends LightningElement {
connectedCallback() {
// Perform setup tasks or attach event listeners
}
}
```
3. **renderedCallback()**: This hook is called after the component's template has been rendered and is applied to the DOM. It's useful for interacting with the DOM after rendering has occurred.
```javascript
import { LightningElement } from 'lwc';
export default class MyComponent extends LightningElement {
renderedCallback() {
// Interact with the DOM after rendering
}
}
```
4. **disconnectedCallback()**: This hook is called when the component is removed from the DOM. It's used for cleanup tasks like removing event listeners or resetting state.
```javascript
import { LightningElement } from 'lwc';
export default class MyComponent extends LightningElement {
disconnectedCallback() {
// Clean up tasks like removing event listeners
}
}
```
5. **reconnectedCallback()**: This hook is called when the component is removed from the DOM and then inserted back into the DOM. It's useful for reinitializing state or performing setup tasks after the component is reinserted.
```javascript
import { LightningElement } from 'lwc';
export default class MyComponent extends LightningElement {
reconnectedCallback() {
// Reinitialize state or perform setup tasks
}
}
```
6. **errorCallback()**: This hook is called when there's an error during rendering, updating, or within an event handler. It's used for error handling and logging.
```javascript
import { LightningElement } from 'lwc';
export default class MyComponent extends LightningElement {
errorCallback(error, stack) {
// Handle errors or log them
}
}
```
These lifecycle hooks provide flexibility and control over the behavior of your Lightning Web Components at various stages of their lifecycle. Utilize them according to your component's requirements for initialization, cleanup, and interaction with the DOM.
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