fetchMethodBodies

Disallow providing a body with GET or HEAD fetch requests.

✅ This rule is included in the ts logical and logicalStrict presets.

The Fetch API throws a TypeError at runtime when the request method is GET or HEAD and a body is provided. This rule detects fetch() calls and new Request() calls that provide a body with a GET or HEAD method.

HTTP methods GET and HEAD are intended to retrieve data without sending a request body. Per the Fetch specification, providing a body with these methods is invalid and will cause the browser or runtime to throw an error.

Examples

❌ Incorrect

const response = await fetch("/api", { body: "data" });

const response = await fetch("/api", { method: "GET", body: "data" });

const response = await fetch("/api", { method: "HEAD", body: "data" });

const request = new Request("/api", { body: "data" });

const request = new Request("/api", { method: "GET", body: "data" });

✅ Correct

const response = await fetch("/api");

const response = await fetch("/api", { method: "POST", body: "data" });

const response = await fetch("/api", { method: "PUT", body: "data" });

const request = new Request("/api", { method: "POST", body: "data" });

Options

This rule is not configurable.

When Not To Use It

If your codebase uses a custom fetch wrapper or polyfill that accepts different options, this rule might produce false positives. You can disable it for files that use such wrappers.

Further Reading

• MDN: fetch()
• MDN: Request()
• Fetch Living Standard

Equivalents in Other Linters

• ESLint: unicorn/no-invalid-fetch-options
• Oxlint: unicorn/no-invalid-fetch-options