import { Diff } from '../Diff' ; const numberDiffSymbol = Symbol ( 'number diff' ) ; const numberDiff = function ( parameters ) : NumberDiff { return { kind : numberDiffSymbol , ... parameters } ; } ; interface NumberDiff extends Diff { kind : typeof numberDiffSymbol ; actual ? : number ; expected ? : number ; difference : number ; } const isNumberDiff = function ( diff ) : diff is NumberDiff { return 'kind' in diff && diff . kind === numberDiffSymbol ; } ; export type { NumberDiff } ; export { isNumberDiff , numberDiff } ;