This recipe migrates code from using deprecated private header fields (_headers, _headerNames) on OutgoingMessage.prototype to their public API equivalents.
Deprecation
Node.js deprecated direct access to private header fields. Use the public methods getHeaders() and getRawHeaderNames() instead.
See DEP0066 for more details.
Usage
Run this codemod with:
npx codemod nodejs/http-outgoingmessage-headers
Before/After
const http = require('http');
function handler(req, res) {
res.setHeader('content-type', 'application/json');
res.setHeader('x-custom-header', '42');
console.log({
- headers: res._headers,
+ headers: res.getHeaders(),
- headerNames: res._headerNames,
+ headerNames: res.getRawHeaderNames(),
- customHeader: res._headers['x-custom-header'],
+ customHeader: res.getHeaders()['x-custom-header'],
- count: Object.keys(res._headers).length,
+ count: Object.keys(res.getHeaders()).length,
});
res.end('Hello World');
}
const server = http.createServer(handler);
server.listen(3000, () => {
console.log('Server running on port 3000');
});
What It Does
- Replaces
res._headers with res.getHeaders()
- Replaces
res._headerNames with res.getRawHeaderNames()
- Updates property access and method calls throughout your codebase
- Works with
ServerResponse and other OutgoingMessage subclasses
Migration Guide
| Deprecated | Replacement |
|---|
res._headers | res.getHeaders() |
res._headerNames | res.getRawHeaderNames() |
Direct access to private fields (prefixed with _) is not part of the public API and can break without notice. Always use public methods.
References
