import { Diff } from '../Diff' ; const setDiffSymbol = Symbol ( 'set diff' ) ; const setDiff = function ( parameters ) : SetDiff { return { kind : setDiffSymbol , ... parameters } ; } ; interface SetDiff extends Diff { kind : typeof setDiffSymbol ; additions : Set < any > ; omissions : Set < any > ; equal : Set < any > ; } const isSetDiff = function ( diff ) : diff is SetDiff { return 'kind' in diff && diff . kind === setDiffSymbol ; } ; export type { SetDiff } ; export { isSetDiff , setDiff } ;