prefer-response-static-json.md

prefer-response-static-json

📝 Prefer Response.json() over new Response(JSON.stringify()).

💼 This rule is enabled in the following configs: ✅ recommended, ☑️ unopinionated.

🔧 This rule is automatically fixable by the --fix CLI option.

Response.json() is a cleaner and more explicit way to create JSON responses. It automatically stringifies the data and sets the correct Content-Type header to application/json, whereas manually using JSON.stringify() requires you to handle the content-type yourself.

The autofix is skipped when the data is undefined, void …, a function, or a class, including TypeScript assertions around them. JSON.stringify() returns undefined for these, while Response.json() throws.

Examples

// ❌
const response = new Response(JSON.stringify(data));

// ✅
const response = Response.json(data);

// ❌
const response = new Response(JSON.stringify(users), {
	headers: {'Content-Type': 'application/json'},
});

// ✅
const response = Response.json(users);

// ❌
const response = new Response(JSON.stringify({error: 'Not found'}), {
	status: 404,
	headers: {'Content-Type': 'application/json'},
});

// ✅
const response = Response.json({error: 'Not found'}, {status: 404});