Tone.js/test/helper/compare/OfflineRender.ts

import { TestAudioBuffer } from "./TestAudioBuffer.js";

export async function OfflineRender(
	callback: (context: OfflineAudioContext) => Promise<void> | void,
	duration = 0.001, channels = 1, sampleRate = 11025
): Promise<TestAudioBuffer> {

	// the offline context
	const offlineContext = new OfflineAudioContext(channels, Math.floor(duration * sampleRate), sampleRate) as unknown as OfflineAudioContext;

	// wait for the callback
	await callback(offlineContext);

	// render the buffer
	const buffer = await offlineContext.startRendering();

	// wrap the buffer
	return new TestAudioBuffer(buffer);
}

/**
 * Returns true if the input passes audio to the output
 */
export async function PassesAudio(
	callback: (
		context: OfflineAudioContext,
		input: ConstantSourceNode,
		output: AudioDestinationNode
	) => Promise<void> | void
): Promise<boolean> {
	const buffer = await OfflineRender(async context => {
		const source = context.createConstantSource() as unknown as ConstantSourceNode;
		source.start(0);
		source.offset.setValueAtTime(0, 0);
		source.offset.setValueAtTime(1, 0.25);
		const destination = context.destination as unknown as AudioDestinationNode;
		await callback(context, source, destination);
	}, 0.5, 1, 11025);
	const sample0 = buffer.getValueAtTime(0) === 0;
	const sample1 = buffer.getValueAtTime(0.2) === 0;
	const sample2 = buffer.getValueAtTime(0.26) as number > 0;
	const sample3 = buffer.getValueAtTime(0.49) as number > 0;
	return sample0 && sample1 && sample2 && sample3;
}

/**
 * Returns true if the callback makes a sound
 */
export async function MakesSound(
	callback: (context: OfflineAudioContext) => Promise<void> | void,
	duration = 0.001, channels = 1, sampleRate = 11025
): Promise<boolean> {
	const buffer = await OfflineRender(callback, duration, channels, sampleRate);
	return !buffer.isSilent();
}