Bitbop Manual

Make pictures, beats, games, and tools with JavaScript.

Start here

Turtle.reset();
while (true) {
  Turtle.move(4);
  sleep(50);
}

Use classic JavaScript with var and function () {}. Run starts fresh. Pause holds the program in place. Step runs one highlighted statement. The Console runs snippets in Global. After Step, it uses the current local scope.

Speaking JavaScript ↗ is an outside ES5 guide. It is written for adults and experienced programmers. Use the complete API reference for studio commands.

Workspace controls

Control	What it does
Format	Makes Code easy to read in one edit. Undo reverses the whole change.
Wrap	Shows long lines on more than one screen line. Your code does not change.
Zoom	Makes Code text larger or smaller.
Examples	Opens one of four finished projects. Undo Example brings back your previous project.
File	Names the project, opens a `.bop` file, saves a copy, or makes a share link.
Panels	Shows or hides parts of the studio.

Control Board

Board.buttonA.onPress(function () {
  Turtle.home();
});

buttonA, buttonB, buttonC, and buttonD provide onPress, onRelease, and a Boolean value.
toggleA and toggleB provide onChange(function (value) {}) and a Boolean value.
sliderA and sliderB provide onChange(function (value) {}) and values from 0 through 100.

Canvas, Turtle, and Paint

Canvas.onClick(function (event) {
  console.log(event.x, event.y);
});

Canvas provides width, height, onClick, onPress, onDrag, and onRelease. Adding a callback turns off finger painting until Stop or a fresh Run.
Turtle provides reset, home, penDown, penUp, color, width, turn, and move.
Paint provides clear, stroke(points, options), and fill(x, y, color).
Canvas Clear clears both layers and returns Turtle home.

Music

Music.play('C4', 0.25, { type: 'triangle' });
sleep(250);
Music.play('E4', 0.25);

Music provides play, stop, stopAll, setInstrument, setVolume, and setEnvelope. Notes can be names such as C4, F#3, and Db5, or MIDI numbers.

Input and timing

prompt(message, defaultValue) asks for text. OK returns text; Cancel returns null.
Keyboard.onPress and Keyboard.onRelease listen to virtual-piano notes.
sleep(milliseconds) pauses the current code path. Use Infinity to wait forever; callbacks still work and Step never waits.
UI.show, UI.hide, and UI.isVisible control the code, controls, canvas, piano, and console panels.

Debugging

console.log, console.warn, and console.error write values to the Console. Add JavaScript's debugger; statement to pause on that Code line. The Console then uses that line's local scope. You can inspect or change variables before you Step or Resume. Start typing and press Tab or Enter to complete supported globals, nested members, parameters, locals, and known object members. Function completion supplies classic-JavaScript parentheses, argument stops, and callback skeletons. Resume and Stop clear the local scope and return the Console to Global.

if (mark === 17) {
  debugger;
}

Use debugger; in Code, not in a Console snippet.

Errors highlight their source line. After Step, run a variable name in the Console to inspect its local value.