import { Diff } from '../Diff' ; const booleanDiffSymbol = Symbol ( 'boolean diff' ) ; const booleanDiff = function ( parameters ) : BooleanDiff { return { kind : booleanDiffSymbol , ... parameters } ; } ; interface BooleanDiff extends Diff { kind : typeof booleanDiffSymbol ; cost : number ; actual ? : boolean ; expected ? : boolean ; } const isBooleanDiff = function ( diff ) : diff is BooleanDiff { return 'kind' in diff && diff . kind === booleanDiffSymbol ; } ; export type { BooleanDiff } ; export { booleanDiff , isBooleanDiff } ;