#491 JSON.stringify

Implement your own version of JSON.stringify() that converts JavaScript values to JSON strings. This is a complex function that handles many edge cases and data types.

Requirements

1. Basic types – null, boolean, number, string
2. Arrays – handle nested arrays and mixed types
3. Objects – handle nested objects, enumerable properties
4. Special values – undefined, Symbol, Function, Date, RegExp
5. Circular references – detect and handle circular object references
6. Edge cases – NaN, Infinity, -Infinity, empty objects/arrays

Key Behaviors

• undefined – omitted from objects, converted to null in arrays
• Symbol – omitted from objects, converted to null in arrays
• Function – omitted from objects, converted to null in arrays
• Date – converted to ISO string
• RegExp – converted to empty object {}
• NaN, Infinity – converted to null
• Circular references – throw TypeError or handle gracefully

Example

stringify({ a: 1, b: [2, 3], c: { d: 4 } });
// '{"a":1,"b":[2,3],"c":{"d":4}}'

stringify({ a: undefined, b: Symbol(), c: function() {} });
// '{}'

stringify([1, undefined, Symbol(), function() {}]);
// '[1,null,null,null]'

stringify(new Date('2023-01-01'));
// '"2023-01-01T00:00:00.000Z"'

// Circular reference
const obj = { a: 1 };
obj.self = obj;
stringify(obj); // Should handle gracefully

Signature

function stringify(value: any): string;

Constraints

• Cannot use native JSON.stringify() – must implement from scratch
• Handle circular references – detect infinite loops
• Follow JSON specification – match standard behavior as closely as possible