How to fix SyntaxError: Cannot use import statement outside a module?

Question

我对这一切都不熟悉，我正在尝试将 Node + Typescript 后端添加到我的 Angular 项目中。但是在导入express后我总是报错。

[ERROR] SyntaxError: Cannot use import statement outside a module.

package.json

{
  "name": "server",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "serve": "ts-node-dev server.ts",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@types/express": "^4.17.11",
    "express": "^4.17.1",
    "ts-node": "^9.1.1",
    "ts-node-dev": "^1.1.6",
    "tslint": "^6.1.3",
    "typescript": "^4.2.4"
  },
}

tsconfig.json

{
  "compilerOptions": {
    "target": "ESNEXT",                                
    "module": "commonjs", 
    "strict": false, 
    "esModuleInterop": true, 
    "skipLibCheck": true,                          
    "forceConsistentCasingInFileNames": true        
  }
}   

server.ts

import * as express from 'express';

const app = express();

app.listen(4201, '127.0.0.', function() {
  console.log('Server is listening on port 4201');
});

我查了一下，最常见的解决方案是将 "type": "module" 添加到 package.json 中，我也这样做了。我也知道这仅适用于 Node 13 及更远的节点，并且我有 Node: 14.15.5.

Answer 1

导入节点模块的最佳做法是使用 require()。您可以使用 require() 函数导入内置核心节点模块、npm 模块以及本地模块。在你的情况下，使用 const express = require( "express" ) 而不是 import * as express from 'express' 并从你的 package.json 中删除“type”：“module”。让我知道这是否适合你。