beep.js

class Beep {
	/**
	 *
	 * @param {AudioContext} audioContext
	 */
	constructor(audioContext = null) {
		this.audioContext = audioContext;
		if (audioContext === null) {
			this.audioContext = new (AudioContext || webkitAudioContext || window.webkitAudioContext)();
		}
	}

	playNote(frequency, duration) {
		const oscillator = this.audioContext.createOscillator();
		const volume = this.audioContext.createGain();
		duration = Math.max(duration, 0.03);
		/*
    const compressor = this.audioContext.createDynamicsCompressor();

    oscillator.frequency.value = frequency;
    oscillator.type = "sine";
    volume.gain.value = 0.1;

    oscillator.connect(volume).connect(compressor).connect(this.audioContext.destination);

    // Ramp up
    volume.gain.exponentialRampToValueAtTime(volume.gain.value, this.audioContext.currentTime+duration);
    // Ramp down
    volume.gain.exponentialRampToValueAtTime(0.0001, this.audioContext.currentTime+decay);

    oscillator.start(this.audioContext.currentTime);
    oscillator.stop(this.audioContext.currentTime+decay+duration);
    */
		oscillator.frequency.value = frequency;
		volume.gain.value = 0.01;
		volume.gain.exponentialRampToValueAtTime(volume.gain.value, this.audioContext.currentTime + duration);
		volume.gain.exponentialRampToValueAtTime(0.0001, this.audioContext.currentTime + 0.3);
		oscillator.connect(volume).connect(this.audioContext.destination);
		oscillator.start();
		oscillator.stop(this.audioContext.currentTime + duration + 0.01);
	}
}