Typescript 錯誤 - “類型已聲明但從未使用” in.ts。 在界面中使用時

Question

為什么 typescript 給我錯誤“'HttpRequest' 已聲明但從未使用。” 什么時候在接口中使用了HttpRequest？ 如何解決這個問題？

import fp from 'fastify-plugin'
import fastify from 'fastify'
import { IncomingMessage } from 'http'
import { Http2ServerRequest } from 'http2'

//'HttpRequest' is declared but never used.
type HttpRequest = IncomingMessage | Http2ServerRequest

declare module 'fastify' {
  interface FastifyRequest<
    HttpRequest,
    Query = fastify.DefaultQuery,
    Params = fastify.DefaultParams,
    Headers = fastify.DefaultHeaders,
    Body = any
  > {
    user: string
  }
}

function plugin(fastify, options, next) {
  fastify.decorateRequest('user', 'userData')
  next()
}

export const reqDecorator = fp(plugin)

這里是 FastifyRequest 接口：

interface FastifyRequest<HttpRequest = IncomingMessage, Query = fastify.DefaultQuery, Params = fastify.DefaultParams, Headers = fastify.DefaultHeaders, Body = any>

Answer 1

您尚未定義類型的名稱，

declare module 'fastify' {
  interface FastifyRequest<
    httpRequest = HttpRequest,

由於IncomingMessage被用作類型，你需要再次為FastifyRequest接口的類型命名，

export interface FastifyRequest<httprequest = IncomingMessage, // added this
Query = fastify.DefaultQuery,
Params = fastify.DefaultParams,
Headers = fastify.DefaultHeaders,
Body = any> {
  // interface fields and methods
}