声明合并不适用于 express 4.17.* 请求类型

Question

我想为 Request 类型添加一个属性，因此我创建了一个文件夹 @types/express 并在此文件夹中添加了包含此内容的文件 index.d.ts。

namespace Express {
  interface Request {
    user: number;
  }
}

在 VSCode 中，当我引用 req.user 时，错误消失了，它甚至显示 user 的类型为 number screenshot that shows that "user" property on the "Request" object is treated right

但是当我启动服务器时，我看到了这样的错误：

/home/myself/web/my-server/node_modules/ts-node/src/index.ts:434
    return new TSError(diagnosticText, diagnosticCodes)
           ^
TSError: ⨯ Unable to compile TypeScript:
src/app.ts:46:7 - error TS2339: Property 'user' does not exist on type 'Request<ParamsDictionary, any, any, ParsedQs>'.

46   req.user;
         ~~~~

    at createTSError (/home/myself/web/my-server/node_modules/ts-node/src/index.ts:434:12)
    at reportTSError (/home/myself/web/my-server/node_modules/ts-node/src/index.ts:438:19)
    at getOutput (/home/myself/web/my-server/node_modules/ts-node/src/index.ts:578:36)
    at Object.compile (/home/myself/web/my-server/node_modules/ts-node/src/index.ts:775:32)
    at Module.m._compile (/home/myself/web/my-server/node_modules/ts-node/src/index.ts:858:43)
    at Module._extensions..js (internal/modules/cjs/loader.js:1220:10)
    at Object.require.extensions.<computed> [as .ts] (/home/myself/web/my-server/node_modules/ts-node/src/index.ts:861:12)
    at Module.load (internal/modules/cjs/loader.js:1049:32)
    at Function.Module._load (internal/modules/cjs/loader.js:937:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)

如果有任何关于如何解决它的想法，我将不胜感激。

附言我对express-session 模块做了同样的事情，并在Session 接口中添加了一个counter 属性，它可以完美运行

Answer 1

安装了@types/express（@types/express-session 也足够了），这应该可以工作：

index.d.ts：

declare module '@types/express-serve-static-core' {
  interface Request {
    user?: User
  }
}

重要的部分是声明合并逻辑是@types/express-serve-static-core 的一部分（参见https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/express-serve-static-core/index.d.ts）。

Answer 2

在失去一些脑细胞后，我为自己提供了答案。 为了解决这个问题，我必须重新创建可以在这个问题中找到的文件夹结构 https://github.com/microsoft/TypeScript/issues/39581

然后我修改了 tsconfig.json，使它的 typeRoots 看起来像这样

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

然后，为了用我的自定义类型增加 Request 类型，我必须使用 import 表达式，所以最后 index.d.ts 文件里面会有这个

declare namespace Express {
  export interface Request {
    user: import("mongoose").Model<import("./../../models/user").User>;
  }
}

为 cmets 中的人配置 tsconfig

{
  "compilerOptions": {
               /* Enable incremental compilation */
    "target": "es5" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', 'ES2018', 'ES2019', 'ES2020', or 'ESNEXT'. */,
    "module": "commonjs" /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', 'es2020', or 'ESNext'. */,
    "lib": [
      "es6"
    ] /* Specify library files to be included in the compilation. */,
    "allowJs": true /* Allow javascript files to be compiled. */,
                     /* Concatenate and emit output to single file. */
    "outDir": "build" /* Redirect output structure to the directory. */,
    "rootDir": "src" /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */,
    "strict": true /* Enable all strict type-checking options. */,
    "noImplicitAny": true /* Raise error on expressions and declarations with an implied 'any' type. */,
                     /* List of root folders whose combined content represents the structure of the project at runtime. */
    "typeRoots": [
      "src/typings/",
      "node_modules/@types/"
    ] /* List of folders to include type definitions from. */,
    "esModuleInterop": true /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */,

    /* Advanced Options */
    "resolveJsonModule": true /* Include modules imported with '.json' extension */,
    "skipLibCheck": true /* Skip type checking of declaration files. */,
    "forceConsistentCasingInFileNames": true /* Disallow inconsistently-cased references to the same file. */
  }
}