如何在 Express 的本地主机上设置 process.env 变量？

Question

I want my code to run for both testing on my localhost, as well as my server.

In heroku there is a GUI to do this, but how do I set these locally?

Answer 1

There are a few ways to set an environment variable before running a program.

You can do it at the same time as you start it:

ENV=test ./start-server

Or in the same shell session:

export ENV=test
./start-server

Answer 2

My preferred solution is to use the npm package called dotenv. If you require it in the entry point to your app it will read in any values in your .env file and make them available to your Node / Express application via process.env. Now you can simply create the necessary.env files in your various environments. You don't need to deal with passing a bunch of arguments to npm scripts. Of course, if you have passwords or API keys in your .env file be sure to add .env to your .gitignore file #captainobvious

Answer 3

If you use nodemon on local (why wouldn't anyone use nodemon?) you can drop a file in the root of your project called nodemon.json. It will make the variables in the file available to your process env vars.

nodemon.json

{
  "env": {
    "MSSQL_DATABASE": "MySqlDb",
    "MSSQL_USER": "MySqlUser",
    "MSSQL_PASSWORD": "MySqlPassword"
  }
}

app.js

const database = process.env.MSSQL_DATABASE;
const username = process.env.MSSQL_USER;
const password = process.env.MSSQL_PASSWORD;

Of course you should add nodemon.json to your.gitignore file, especially if it contains sensitive information.