How to get callback when Node.js spawn execution is done

The built-in child_process Node.js package has a spawn method that allows you to run a terminal command.

There’s no built-in way of running a function when the command has finished executing, but spawn does give us access to a “done” event when the command finishes executing.

const { spawn } = require("child_process");

const command = spawn("git clone https://github.com/benborgers/potion", {
  shell: true,
});

command.on("close", () => {
  // Code to run when the command finishes
});

You could even wrap this into a nice, reusable function:

const { spawn } = require("child_process");

// Reusable function:
const executeCommand = (textToExecute) =>
  new Promise((resolve) => {
    const command = spawn(textToExecute, { shell: true });
    command.on("close", () => resolve());
  });

// Usage:
const main = async () => {
  await executeCommand("git clone https://github.com/benborgers/potion");

  // Do something here that will only happen after the command has finished.
};
main();