创建一个类似global.d.ts的文件

declare global {
  namespace NodeJS {
    interface ProcessEnv {
      SECRET: string;
    }
  }
}
export {};

教程由克里斯蒂安Höller

通过运行npm i @types/node安装@types/node 在tsconfig中添加"types": ["node"]。json文件在compilerSection部分。

使用节点进程的最佳和最简单的方法。你的typescript项目中的env是首先用tsc编译，然后用node提供你的env var运行编译后的javascript文件。ts是你想要的输出目录也是编译文件的名称，我使用dist作为输出目录和index.js为例):

cd my-typescriptproject
tsc
NODE_ENV=test node ./dist/index.js

重要提示:如果你有一个web应用程序，你正在使用webpack。定义流程。Env在你的窗户上，那么这些就是你要找的类型:

declare namespace process {
    let env: {
        // this is optional, if you want to allow also
        // other values than the ones listed below, they will have type 
        // string | undefined, which is the default
        [key: string]: string
        commit_hash: string
        build_time: string
        stage: string
        version: string
        // ... etc.
    }
}

您可以为此使用类型断言

Sometimes you’ll end up in a situation where you’ll know more about a value than TypeScript does. Usually this will happen when you know the type of some entity could be more specific than its current type. Type assertions are a way to tell the compiler “trust me, I know what I’m doing.” A type assertion is like a type cast in other languages, but performs no special checking or restructuring of data. It has no runtime impact, and is used purely by the compiler. TypeScript assumes that you, the programmer, have performed any special checks that you need.

例子

const nodeEnv: string = (process.env.NODE_ENV as string);
console.log(nodeEnv);

或者，您可能会发现像env-var这样的库更适合这个特定的目的——

在node.js中使用正确类型加载和清除环境变量的解决方案

下面是一个简短的函数，它保证会拉动进程。将Env值作为字符串—或以其他方式抛出错误。

对于更强大(但也更大)的东西，这里的其他人建议使用env-var。

/**
 * Returns value stored in environment variable with the given `name`.
 * Throws Error if no such variable or if variable undefined; thus ensuring type-safety.
 * @param name - name of variable to fetch from this process's environment.
 */
export function env(name: string): string {
  const value = process.env[name];

  if (!value) {
    throw new Error(`Missing: process.env['${name}'].`);
  }

  return value;
}

然后你应该能够编写如下代码:

let currentEnvironment: string;
currentEnvironment = env('NODE_ENV');