I would like to open source a project that I have been working on. Currently, my package.json contains a build config that lists an API key that I want to keep private. Can I access environment variables from package.json and reference the key that way, or is there a way to extract the build config to another file and access it from package.json? I have found plenty of questions referencing mutating environment variables from package.json but I haven't come across how to read them.

{
  "name": "name",
  "version": "0.7.1",
  "build": {
    "apikey": "asdfw345r34t...",
  }
}