node express + typescript module not found 错误

Question

我已经用 typescript 设置了一个简单的 node express 应用程序。

我想在 index.ts 文件中添加一个errorMiddleware。

当我启动服务器时出现此错误：

    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (D:\ActiveProjects\rugBE\src\index.ts:1:1)
    at Module._compile (node:internal/modules/cjs/loader:1101:14)
    at Module.m._compile (C:\Users\UserName\AppData\Roaming\npm\node_modules\ts-node\src\index.ts:1371:23)
    at Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Object.require.extensions.<computed> [as .ts] (C:\Users\UserName\AppData\Roaming\npm\node_modules\ts-node\src\index.ts:1374:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ 'D:\\ActiveProjects\\rugBE\\src\\index.ts' ]

我的 package.json：

{
  "name": "rugbe",
  "version": "1.0.0",
  "description": "",
  "main": "src/index.ts",
  "scripts": {
    "dev": "nodemon src/index.ts"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "ts-node": "^10.4.0"
  },
  "devDependencies": {
    "@types/express": "^4.17.13",
    "@types/node": "^16.11.19",
    "nodemon": "^2.0.15",
    "typescript": "^4.5.4"
  }
}

tsConfig：

{
  "compilerOptions": {
    "module": "commonjs",
    "esModuleInterop": true,
    "target": "es6",
    "moduleResolution": "node",
    "sourceMap": true,
    "outDir": "dist",
    "baseUrl": "src",
    "paths": {
      "Handlers/*": ["Handlers/*"]
    },
    "resolveJsonModule": true
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}

index.ts:

import express from "express";
import errorMiddleWare from "Handlers/Error/handlerError"; // error here
// import notFoundMiddleWare from "Handlers/Error/notFound";
const app = express();
const port = 5000;

//@ts-ignore
app.get("/api", (_, res) => {
  res.send("Hello World");
});

//notFound

// error
app.use(errorMiddleWare);

// app.all("*", notFoundMiddleWare);

app.listen(port);

我要导入的中间件：

//@ts-ignore
const errorMiddleWare = (err, req, res, next) => {
  // note params are the ones that tell if the errors should come here
  const { statusCode, message } = err;
  res.status(500).json({
    status: "error",
    statusCode: 500,
    message,
  });

  next();
};

export default errorMiddleWare;

我错过了什么？

Answer 1

Handlers 是“裸”路径。当你告诉节点导入一个不是以/ 或./（或../）开头的文件时，它会在你的node_modules 目录中查找具有该名称的模块。

为了添加相对于您当前目录（和其他文件）的文件，请在其前面加上 ./。如果您想全面了解 cjs（CommonJS 模块）模块加载的工作原理，请指定完整算法 here。

// Before, loads a Handlers package from node_modules
import errorMiddleWare from "Handlers/Error/handlerError"; // error here

// After, looks for a handlerError module in an
// Error folder inside the Handlers folder inside the current one
import errorMiddleWare from "./Handlers/Error/handlerError"; // error here