types: added http header types to reply

test/types/reply.test-d.ts

@@ -22,12 +22,12 @@ const getHandler: RouteHandlerMethod = function (_request, reply) {
   expectType<number>(reply.statusCode)
   expectType<boolean>(reply.sent)
   expectType<((payload?: unknown) => FastifyReply)>(reply.send)
-  expectType<(key: string, value: any) => FastifyReply>(reply.header)
-  expectType<(values: {[key: string]: any}) => FastifyReply>(reply.headers)
-  expectType<(key: string) => number | string | string[] | undefined>(reply.getHeader)
-  expectType<() => { [key: string]: number | string | string[] | undefined }>(reply.getHeaders)
-  expectType<(key: string) => FastifyReply>(reply.removeHeader)
-  expectType<(key: string) => boolean>(reply.hasHeader)
+  expectAssignable<(key: string, value: any) => FastifyReply>(reply.header)
+  expectAssignable<(values: {[key: string]: any}) => FastifyReply>(reply.headers)
+  expectAssignable<(key: string) => number | string | string[] | undefined>(reply.getHeader)
+  expectAssignable<() => { [key: string]: number | string | string[] | undefined }>(reply.getHeaders)
+  expectAssignable<(key: string) => FastifyReply>(reply.removeHeader)
+  expectAssignable<(key: string) => boolean>(reply.hasHeader)
   expectType<{(statusCode: number, url: string): FastifyReply; (url: string): FastifyReply }>(reply.redirect)
   expectType<() => FastifyReply>(reply.hijack)
   expectType<() => void>(reply.callNotFound)
@@ -162,3 +162,22 @@ server.get<InvalidReplyHttpCodes>('get-invalid-http-codes-reply-error', async fu
     999: false
   })
 })
+
+const httpHeaderHandler: RouteHandlerMethod = function (_request, reply) {
+  // accept is a header provided by @types/node
+  reply.getHeader('accept')
+  reply.getHeaders().accept // eslint-disable-line no-unused-expressions
+  reply.hasHeader('accept')
+  reply.header('accept', 'test')
+  reply.headers({ accept: 'test' })
+  reply.removeHeader('accept')
+
+  // x-fastify-test is not a header provided by @types/node
+  // and should not result in a typing error
+  reply.getHeader('x-fastify-test')
+  reply.getHeaders()['x-fastify-test'] // eslint-disable-line no-unused-expressions
+  reply.hasHeader('x-fastify-test')
+  reply.header('x-fastify-test', 'test')
+  reply.headers({ 'x-fastify-test': 'test' })
+  reply.removeHeader('x-fastify-test')
+}

types/reply.d.ts

@@ -6,7 +6,7 @@ import { FastifyRequest } from './request'
 import { RouteGenericInterface } from './route'
 import { FastifySchema } from './schema'
 import { FastifyReplyType, FastifyTypeProvider, FastifyTypeProviderDefault, ResolveFastifyReplyType } from './type-provider'
-import { CodeToReplyKey, ContextConfigDefault, HttpKeys, RawReplyDefaultExpression, RawRequestDefaultExpression, RawServerBase, RawServerDefault, ReplyDefault, ReplyKeysToCodes } from './utils'
+import { CodeToReplyKey, ContextConfigDefault, HttpKeys, RawReplyDefaultExpression, RawRequestDefaultExpression, RawServerBase, RawServerDefault, ReplyDefault, ReplyKeysToCodes, HttpHeader } from './utils'
 
 export interface ReplyGenericInterface {
   Reply?: ReplyDefault;
@@ -48,15 +48,12 @@ export interface FastifyReply<
   statusCode: number;
   sent: boolean;
   send(payload?: ReplyType): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
-  header(key: string, value: any): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
-  headers(values: {[key: string]: any}): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
-  getHeader(key: string): number | string | string[] | undefined;
-  getHeaders(): {
-    // Node's `getHeaders()` can return numbers and arrays, so they're included here as possible types.
-    [key: string]: number | string | string[] | undefined;
-  };
-  removeHeader(key: string): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
-  hasHeader(key: string): boolean;
+  header(key: HttpHeader, value: any): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
+  headers(values: Partial<Record<HttpHeader, number | string | string[] | undefined>>): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
+  getHeader(key: HttpHeader): number | string | string[] | undefined;
+  getHeaders(): Record<HttpHeader, number | string | string[] | undefined>;
+  removeHeader(key: HttpHeader): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
+  hasHeader(key: HttpHeader): boolean;
   // Note: should consider refactoring the argument order for redirect. statusCode is optional so it should be after the required url param
   redirect(statusCode: number, url: string): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;
   redirect(url: string): FastifyReply<RawServer, RawRequest, RawReply, RouteGeneric, ContextConfig, SchemaCompiler, TypeProvider>;

types/utils.d.ts

@@ -78,3 +78,12 @@ export type RecordKeysToLowercase<Input> = Input extends Record<string, unknown>
     ]: Input[Key];
   }
   : Input;
+
+type OmitIndexSignature<T> = {
+  [K in keyof T as string extends K ? never : number extends K ? never : K]: T[K];
+};
+
+/**
+ * HTTP header strings
+ */
+export type HttpHeader = keyof OmitIndexSignature<http.OutgoingHttpHeaders> | (string & {}); // eslint-disable-line @typescript-eslint/ban-types