How to Export Environment Variables on Mac and Windows

I'm building a desktop app for managing SVG icon libraries called SVGX.app.

It uses Electron and Svelte, as well as Forge which is a helpful tool for creating and publishing such apps. I'm also using this template as a starter.

My plan was to offer two versions of the app: paid and demo. Notice I said "was" - I'm still debating the details. Anyway, I thought the demo would be a stripped edition of the full app, lacking certain features.

I decided that one way to accomplish this in an Electron app would be to create a couple of extra build tasks in package.json, and then run the commands like so:

• npm run start or yarn start - builds the full Mac version
• npm run start-demo or yarn start-demo - builds the demo Mac version
• npm run start-win or yarn start-win - builds the full Windows version
• npm run start-win-demo or yarn start-win-demo - builds the demo Windows version

Each of these tasks would export a DEMO flag as an environment variable, that my app could use to conditionally "guard" features when the flag is false.

Well, on Mac it's simple: just add export \"DEMO=yes\" in the script (notice the escaped quotes), and call it a day. The Electron app would read the DEMO variable with process.env.DEMO. Simple, right?

Not so fast. It turns out you can't use this syntax to export environment variables in Windows (I use Git Bash for my terminal). The build process will fail with an error:

'export' is not recognized as an internal or external command, operable program or batch file.

I feel I should have known this, but I code almost exclusively on a Mac, so I never ran into this situation before. What does work is to use set \"DEMO=yes\" instead.

So my script becomes what you see below:

{
  "name": "...",
  "productName": "...",
  "version": "...",
  "description": "...",
  "main": "...",
  "scripts": {
    "start": "export \"DEMO=no\" && concurrently \"npm:svelte-dev\" \"electron-forge start\"",
    "start-demo": "export \"DEMO=yes\" && concurrently \"npm:svelte-dev\" \"electron-forge start\"",
    "start-win": "set \"DEMO=no\" && concurrently \"npm:svelte-dev\" \"electron-forge start\"",
    "start-win-demo": "set \"DEMO=yes\" && concurrently \"npm:svelte-dev\" \"electron-forge start\"",
  },
  ...
}

In summary:

• use export on Mac
• use set on Windows