A composable to modify/change attributes/props (e.g. `class` or `style`) of slotted elements when using v-slot in vue.js [wip]. Only to be used in render (aka `h()`) functions.

useModifiedSlot.ts

import type { SetupFunction } from '@nuxtjs/composition-api'
import type { CreateElement, VNode } from 'vue'

function useModifiedSlot(
  slotName: string,
  dataToAppend: Required<Parameters<CreateElement>>['1'],
) {
  const slot = getCurrentInstance()?.slots[slotName]
  const slotVnode = Array.isArray(slot) && slot[0].data

  if (slotVnode) {
    slotVnode.staticClass = `${slotVnode.staticClass ?? ''} ${dataToAppend.staticClass ?? ''}`
    // TODO: maninak implement assigning all other fields and extract function to standalone file in /composables
  } else {
    throw new Error(
      "Reached no man's land inside `useModifiedSlot()`. Maybe this use case isn't covered by the implementation..?",
    )
  }

  // Type assertion necessary due to error in original typings for `getCurrentInstance`. `Array.isArray(slot)` too.
  return slot as VNode[] | undefined
}