Learn about the lifecycle hooks in Salesforce Lightning Web Components (LWC) and when to use them.
In Salesforce, the lifecycle of an LWC (Lightning Web Component) refers to the various stages that a component goes through, from creation to destruction. LWC lifecycle hooks allow developers to run specific code at different stages of the component's lifecycle. These hooks help in managing the component's initialization, data fetching, and cleanup tasks.
constructor()When it's called: The constructor is called when the component is created. It’s called only once during the lifecycle.
Use Case: Initialize properties or set default values. Avoid making asynchronous calls (e.g., data fetching) here as it can block component rendering.
connectedCallback()When it's called: Called when the component is inserted into the DOM. It is executed after the component is first rendered.
Use Case: This is a good place to make asynchronous calls such as data fetching from an Apex method, event listeners, or setting up third-party libraries. It is executed only once when the component is inserted into the DOM.
renderedCallback()When it's called: Called after every render of the component. It’s executed each time the component updates its DOM, such as when data or state changes.
Use Case: Use this hook if you need to interact with or modify the DOM after it is updated. It is useful for things like measuring the size of DOM elements or interacting with third-party JS libraries that need to manipulate the DOM.
disconnectedCallback()When it's called: Called when the component is removed from the DOM. This is the best place to clean up any side effects, event listeners, or timers.
Use Case: Use this hook for cleanup operations, such as removing event listeners or canceling network requests, to avoid memory leaks when the component is removed.
errorCallback(error, stack)When it's called: This hook is triggered if there is an error during rendering or in any of the component's lifecycle hooks.
Use Case: Use this hook to catch and handle errors that occur during the lifecycle. You can display custom error messages or log errors for debugging purposes.