declare namespace safeJsonStringify { function ensureProperties(obj: any): object; } // see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#The_replacer_parameter type ReplacerFn = (key: any, value: any) => any; declare function safeJsonStringify( data: object, replacer?: ReplacerFn | any[] | null, space?: string | number, ): string; export = safeJsonStringify;