@qfetch/middleware-headers

Fetch middleware for adding default headers to outgoing requests.

Overview

Sets default headers on outgoing requests using the standard Headers API. Request headers take precedence over middleware headers. Supports both plain objects and Headers instances. Header names are case-insensitive per HTTP specification.

Intended for use with @qfetch/core.

Installation

npm install @qfetch/middleware-headers

Quick Start

import { withHeaders } from '@qfetch/middleware-headers';
import { withBaseUrl } from '@qfetch/middleware-base-url';
import { withAuthorization } from '@qfetch/middleware-authorization';
import { compose } from '@qfetch/core';

// Build an API client with default headers for JSON communication
const api = compose(
  withHeaders({
    'Content-Type': 'application/json',
    'Accept': 'application/json',
    'X-Client-Version': '1.0.0',
  }),
  withBaseUrl('https://api.example.com/v1/'),
)(fetch);

// All requests include the default headers
await api('users', {
  method: 'POST',
  body: JSON.stringify({ name: 'Alice' }),
});

Documentation

For complete API reference, examples, and type definitions, see the API documentation.

Standards References

• RFC 9110 - HTTP Semantics: Header Fields - HTTP header field specification
• MDN: Headers - Browser implementation documentation