import isObject from '../utils/is-object' ; export const VALUE = Symbol ( '__value__' ) ; export default class Change { [ VALUE ] : unknown ; constructor ( value ) { this [ VALUE ] = value ; } } export const isChange = ( maybeChange ) : maybeChange is Change => isObject ( maybeChange ) && VALUE in ( maybeChange as any ) ; export function getChangeValue ( maybeChange ) { if ( isChange ( maybeChange ) ) { return maybeChange [ VALUE ] ; } }