getUnmountedInstances

getUnmountedInstances<T extends Base = Base>(name: string, root?: ParentNode): T[]
getUnmountedInstances<T extends Base = Base>(el: Element): T[]

The instances of a component name that were built and are not mounted, in DOM order — or the same on one element, in mount order.

Usage

import { getUnmountedInstances } from '@studiometa/js-toolkit';

getUnmountedInstances('Video').length;

What this population is

It is small and specific. It is what a reversible mount strategy leaves behind: in-view and media: unmount their instance when the condition stops holding and keep it for the crossing back, so the instance stays in the element's map with $isMounted === false.

A constructor that succeeded before a failing mounted() lands here too.

What is not here

• A declaration whose class never arrived. A lazy entry that has not loaded has no instance at all.
• A declaration withdrawn by a breakpoint. That instance is unmounted and deleted from the map, so the name later declared again builds a new one.
• A component still waiting on a mount strategy. It has never been constructed.

Neither has an instance, so neither can be in a list of them.

The two overloads

(name: string, root?: ParentNode): T[]
(el: Element): T[]

• The name form searches the descendants of root, which defaults to the document. root is a ParentNode and the call is querySelectorAll, so it never matches root itself.
• The element form reads the element's instance map directly and never consults the DOM, so it answers for a detached element as readily as for a connected one. The name form cannot: document.querySelectorAll() does not see a detached element. Pass the detached root as root when a name lookup has to reach inside it.

How the narrowing works

selectorFor(name) over-matches on purpose — it lists the responsive spellings of data-component too — and the instance-map read is what removes an inactive declaration, because a breakpoint-withdrawn component is destroyed and deleted from the map.

A matching element with no instance is skipped, and that is the whole narrowing. There is no mount filter, because it never did that work.