beatbox.js-export

beatbox.js-export allows exporting beatbox.js patterns as MP3 or WAV files.

It relies on the following libraries:

• wasm-media-encoders for MP3 encoding
• wav-encoder for WAV encoding

Usage

import { Beatbox } from "beatbox.js";
import { exportMP3, exportWAV } from "beatbox.js-export";
import saveAs from "save-as";

// See beatbox.js documentation. Note that the "repeat" parameter is ignored in the context of exporting.
var player = new Beatbox(pattern, beatLength, repeat);

let blob = await exportMP3(player);
saveAs(blob, "song.mp3");

blob = await exportWAV(player);
saveAs(blob, "song.wav");

Progress

An optional onProgress callback can be passed to track the progress:

let blob = await exportMP3(player, {
	onProgress: (progress) => {
		// Progress is a number between 0 and 1
		console.log(progress);
	}
});

Abort

You can pass an abort signal to cancel the export. This will cause the export function to throw the signal cause.

const abortController = new AbortController();
document.getElementById("cancel-button").addEventListener("click", () => {
	abortController.abort();
});

try {
	const blob = await exportMP3(player, { signal });
	saveAs(blob, "song.mp3");
} catch (err) {
	if (err instanceof DOMException && err.name === "AbortError") {
		// Ignore
	}

	throw err;
}

Upgrading

Check out the changelog for notes about breaking changes.