javascript-stringify/dist/types.d.ts

Stringify is to `eval` as `JSON.stringify` is to `JSON.parse`

/**
 * Call `next()` every time you want to stringify a new value.
 */
export declare type Next = (value: any, key?: PropertyKey) => string | undefined;
/**
 * Stringify a value.
 */
export declare type ToString = (value: any, space: string, next: Next, key: PropertyKey | undefined) => string | undefined;