uppy/packages/@uppy/react/src/useUppy.js

import { useEffect, useRef } from 'react'
import { Uppy as UppyCore } from '@uppy/core'

export default function useUppy (factory) {
  if (typeof factory !== 'function') {
    throw new TypeError('useUppy: expected a function that returns a new Uppy instance')
  }

  const uppy = useRef(undefined)
  if (uppy.current === undefined) {
    uppy.current = factory()

    if (!(uppy.current instanceof UppyCore)) {
      throw new TypeError(`useUppy: factory function must return an Uppy instance, got ${typeof uppy.current}`)
    }
  }

  useEffect(() => {
    return () => {
      uppy.current?.close({ reason: 'unmount' })
      uppy.current = undefined
    }
  }, [uppy])

  return uppy.current
}