Example

CommonJS

          
            1const { runIfMain } = require("./mainCheck");3function main() {4  console.log("Running directly as a script!");5}7runIfMain(null, module, require.main, main);
          
        

ES Module

          
            1import { runIfMain } from "./mainCheck.mjs";3runIfMain(import.meta.url, null, null, () => {4  console.log("Running directly in ESM!");5});