Motivation

Projects often rely on environmental variables stored in a .env file to run... and because these variables sometimes contain sensitive data, we never add them to source control. Instead, these variables are added e.g. to a .env.example file so it's easy to get the project running for other developers. However, it's very easy to forget to update this file when a variable is added/updated in .env (during development). This can make it difficult for devs to get the project running (locally) because they rely on .env.example file to setup their environment (with their own configs).

Enter sync-dotenv 🔥

Description

sync-dotenv automates the process of keeping your .env in sync with .env.example.

Installation

$ npm install -g sync-dotenv

Install as a dev dependency (recommended)

$ npm install -D sync-dotenv

Usage

By default, sync-dotenv looks for a .env in your working directory and attempt to sync with .env.example when no argument is provided. Failure to find these files will cause the sync to fail.

$ sync-dotenv

Alternatively, you can use the --env and --sample flag to specify the source and destination file.

$ sync-dotenv --env foo/.env --sample bar/.env.example

Also, in the situation where you want to keep multiple files in sync with one source env file you can make use of the --samples flag specifying a globbing pattern to match:

$ sync-dotenv --env foo/.env --samples "env-samples/*"

# note: glob pattern should be provided as a string as shown above

For CLI options, use the --help flag

$ sync-dotenv --help

Examples

Sync (with .env.example) before every commit using husky

// package.json
{
  "scripts": {
    "env": "sync-dotenv"
  },
  "husky": {
    "hooks": {
      "pre-commit": "npm run env",
    }
  }
}

Or with file other than .env.example

{
  "scripts": {
-    "env": "sync-dotenv"
+    "env": "sync-dotenv --sample .env.development"
  }
}

Preserving variables in sample env

Sometimes you need to preserve certain variables in your example env file, you can optionally allow this by adding a sync-dotenv config in package.json like so

// package.json
"scripts": {
  ...
},
"sync-dotenv": {
  "preserve": ["CHANNEL"]
}

Avoid comments or empty lines in sample env

You might not want to copy empty lines or comments to your sample env, in this case you can still use sync-dotenv config in package.json with the following:

// package.json
"scripts": {
  ...
},
"sync-dotenv": {
  "emptyLines": true,
  "comments": false
}

Note that you can still combine those options with preserve.

Related

• parse-dotenv - zero dependency .env to javascript object parser

Contributors

Thanks goes to these wonderful people (emoji key):

This project follows the all-contributors specification. Contributions of any kind welcome!

License

This project is licensed under MIT