Svelte ondestroy - Javascript

Svelte is a powerful JavaScript framework that allows developers to create highly efficient web applications. One of the key features of Svelte is its ability to handle the destruction of components, which is important for managing the overall performance of your application.

The ondestroy function is a callback function in Svelte that is triggered when the component is removed from the DOM. This function is useful for performing cleanup operations such as removing event listeners or releasing resources used by the component.

Here is an example of how ondestroy can be used to remove event listeners:

<script>
  import { onMount, onDestroy } from 'svelte';

  let count = 0;

  const handleClick = () => {
    count++;
    console.log(`Clicked ${count} times`);
  };

  onMount(() => {
    window.addEventListener('click', handleClick);
  });

  onDestroy(() => {
    window.removeEventListener('click', handleClick);
  });
</script>

<button>Click me</button>

In this example, we add an event listener to the window object in the onMount function, and remove it in the onDestroy function. This ensures that the event listener is cleaned up properly when the component is removed from the DOM.

Overall, the ondestroy function is a valuable tool for managing the lifecycle of components in Svelte, and can help you create high-performance web applications with ease.