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

在使用process.env之前添加即可。NODE_ENV跟随行:

declare var process : {
  env: {
    NODE_ENV: string
  }
}

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

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。

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.
    }
}

我写了一个模块来简化它。它没有依赖关系，所以是相当轻量级的。它也适用于dotenv，您可以传递一个自定义进程。Env到Env .from函数，如果需要的话。

在一些回答中已经提到了它，但这里有一个例子:

使用yarn/npm安装:

npm install env-var --save

然后读取变量:

import * as env from 'env-var'

// Read NODE_ENV and verify that:
// 1) it is set using the required() function
// 2) it is either 'dev' or 'prod'
// 3) throw a runtime exception if conditions #1 or #2 fail
const environment = env.get('NODE_ENV').required().asEnum(['dev', 'prod'])

// Intellisense will suggest 'dev' or 'prod'
if (environment === 'dev') {
  console.log('yep, this is dev')
} else {
  console.log('looks like this is prod')
}

或另一个:

import { get } from 'env-var'

// Read the GitHub token. It could be undefined
const githubToken = get('GITHUB_TOKEN').asString()

// Read MAX_CONCURRENCY, or default to 5. Throw an error if it's
// not set to a positive integer value
const concurrencyLimit = get('MAX_CONCURRENCY').default(5).asIntPositive()

function callGitApi (token: string, concurrency: number) { /* implementation */ }

// TS Error: Argument of type 'string | undefined' is not assignable to
// parameter of type 'string'.
callGitApi(githubToken, concurrencyLimit)