Typescript 如何使用express在回调函数之间传递值？

我正在尝试文档中附带的方法，以按特定顺序进行函数调用链，因此我希望将值从

cb0

传递到

cb1

（或

cb2

），目前我正在

req

对象中设置一个属性，并从另一个处理程序访问它，这一切正常

const express = require('express');
const app = express();
const PORT = 8000;

const cb0 = function (req, res, next) {
  console.log('CB0');
  req.cb0val = 'Hello';
  next();
}

const cb1 = function (req, res, next) {
  console.log('CB1');
  req.cb1val = 'World';
  next();
}

const cb2 = function (req, res) {
  res.send(`Hey, ${req.cb0val} ${req.cb1val}`);
}

app.get('/', [cb0, cb1, cb2])

app.listen(PORT, () => {
  console.log(`⚡️[server]: Server is running at https://localhost:${PORT}`);
});

使用

typescript

import express from 'express';
const app = express();
const PORT = 8000;

const cb0: express.RequestHandler = function (req: express.Request, res: express.Response, next: Function) {
  console.log('CB0');
  req.cb0val = 'Hello';
  next();
}

const cb1: express.RequestHandler = function (req: express.Request, res: express.Response, next: Function) {
  console.log('CB1');
  req.cb1val = 'World';
  next();
}

const cb2: express.RequestHandler = function (req: express.Request, res: express.Response) {
  res.send(`Hey, ${req.cb0val} ${req.cb1val}`);
}

app.get('/example/c', [cb0, cb1, cb2])

app.listen(PORT, () => {
  console.log(`⚡️[server]: Server is running at https://localhost:${PORT}`);
});

因为我正在将

req

的类型设置为

express.Request

我无法设置该类型的新属性，因此出现以下错误：

index.ts:7:7 - error TS2339: Property 'cb0val' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs>'.

7   req.cb0val = 'Hello';
        ~~~~~~
index.ts:13:7 - error TS2339: Property 'cb1val' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs>'.

13   req.cb1val = 'World';
         ~~~~~~
index.ts:18:24 - error TS2339: Property 'cb0val' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs>'.

18   res.send(`Hey, ${req.cb0val} ${req.cb1val}`);
                          ~~~~~~
index.ts:18:38 - error TS2339: Property 'cb1val' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs>'.

18   res.send(`Hey, ${req.cb0val} ${req.cb1val}`);
                                        ~~~~~~

index.ts:7:7-错误TS2339:类型“Request”上不存在属性“cb0val”。
7 req.cb0val='你好'；
~~~~~~
index.ts:13:7-错误TS2339:类型“Request”上不存在属性“cb1val”。
13 req.cb1val=‘世界’；
~~~~~~
index.ts:18:24-错误TS2339:类型“Request”上不存在属性“cb0val”。
18 res.send（`Hey，${req.cb0val}${req.cb1val}`）；
~~~~~~
index.ts:18:38-错误TS2339:类型“Request”上不存在属性“cb1val”。
18 res.send（`Hey，${req.cb0val}${req.cb1val}`）；
~~~~~~

---

在不将

express.Request

的类型更改为

any

的情况下，处理此场景的正确方法是什么？

您可以使用一种称为声明合并的方法

在项目中的某个地方创建一个名为

express.d.ts

的文件。这通常是在项目根目录中的

@types

文件夹中创建的（

@types/express.d.ts

）

此文件的内容应为

declare namespace Express {
    interface Request {
        cb0val: string
        // other custom properties ...
    }
}

在tsconfig中，设置

typeRoot

或将新文件添加到

types

字段

"typeRoots": [
  "@types/",
  "node_modules/@types/"
]