Function onMount

onMount<T>(fn): void
The onMount function schedules a callback to run as soon as the component has been mounted to the DOM. It must be called during the component's initialisation (but doesn't need to live inside the component; it can be called from an external module).

If a function is returned synchronously from onMount, it will be called when the component is unmounted.

onMount does not run inside a server-side component.

https://svelte.dev/docs/svelte#onmount
Type Parameters
- T
Parameters
- fn: (() => NotFunction<T> | Promise<NotFunction<T>> | (() => any))
  - - (): NotFunction<T> | Promise<NotFunction<T>> | (() => any)
    - Returns NotFunction<T> | Promise<NotFunction<T>> | (() => any)
Returns void