Skip to main content
Version: Next

Interactive Development (REPL & Notebook)

After your program runs on the device, you can send more BlueScript code without editing files and running bscript project run again.

Try the Notebook​

This walkthrough continues from Blink LED (GPIO package installed, LED wired).

1. Shorten index.bs​

Keep the entry file small so the Notebook opens quickly. Setup belongs here; experiments go in cells.

src/index.bs
import { GPIO, PinMode, PinLevel } from "gpio";

// CHANGE 2 TO 23 IF USING AN EXTERNAL LED
const led = new GPIO(2, PinMode.InputOutput);

console.log("LED ready.");

The led variable stays available in later cells.

2. Start the Notebook​

bscript project run --with-notebook

The CLI runs index.bs, then opens the Notebook in your browser (http://localhost:3000). Leave the terminal open until you are done.

BlueScript Notebook

3. Run cells​

  1. Type code in the bottom cell.
  2. Press Shift+Enter (or the play button).
  3. See console.log output on the right.

Example—run these as two separate cells:

console.log("LED on");
led.write(PinLevel.High);
console.log("LED off");
led.write(PinLevel.Low);

Press Ctrl+D in the terminal to exit.

Other modes​

Project REPL​

bscript project run --with-repl

After index.bs runs, type one line at the > prompt. Installed packages (e.g. gpio) can be imported here. Exit with Ctrl+D.

Global REPL​

bscript repl -b esp32
# or, without hardware:
bscript repl -b host

Use this for quick syntax checks without a project. GPIO and other installed libraries are not available. Exit with Ctrl+D.

Good to know​

  • Device name: Notebook and Project REPL connect using deviceName in bsconfig.json. Global REPL uses the -d flag instead. The name must match what was set during bscript board flash-runtime. See bsconfig.json.
  • Code on the device is lost after a reboot—run the command again to re-upload.