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AudioWorklet Start

Use this path to run the package-owned WASM processor in a browser audio graph.

Release state: npm is unreleased. The public install command is intentionally disabled until a version-matched smoke test passes.

Serve the app over HTTPS or localhost. Direct file: loading is unsupported because ordinary browser module, AudioWorklet, and WASM security rules generally reject it. Start from a user gesture, keep processor/WASM/meta assets same-origin with correct MIME types, and permit them in CSP.

Browser audio

Copy the package’s complete dist/ directory to /vendor/@effetune/dsp/dist/. This import map resolves the package’s bare Worklet specifier; the module script is the runnable Start below.

<!doctype html>
<meta charset="utf-8">
<title>EffeTune AudioWorklet Start</title>
<script type="importmap">
{
  "imports": {
    "@effetune/dsp/worklet": "/vendor/@effetune/dsp/dist/worklet.js"
  }
}
</script>
<script type="module" src="./audioworklet-start.js"></script>

import { EffeTuneNode } from '@effetune/dsp/worklet';

export async function createVolumeGraph(
  context,
  source,
  destination = context.destination,
  options = {}
) {
  if (typeof OfflineAudioContext === 'undefined' ||
      !(context instanceof OfflineAudioContext)) {
    await context.resume();
  }
  const node = await EffeTuneNode.create(context, {
    version: 1,
    chain: [{
      id: 'volume',
      type: 'Volume',
      parameters: { volume: -6 }
    }]
  }, { channels: 2, seed: 0, ...options });
  source.connect(node).connect(destination);
  return {
    node,
    async setVolume(volume) {
      await node.setParam('volume', 'volume', volume);
    },
    async close() {
      source.disconnect();
      node.disconnect();
      node.close();
      if (typeof context.close === 'function') await context.close();
    }
  };
}

if (typeof document !== 'undefined') {
  const controls = document.createElement('p');
  controls.innerHTML = '<button type="button">Start</button> ' +
    '<button type="button" disabled>Stop</button>';
  document.body.append(controls);
  const [startButton, stopButton] = controls.querySelectorAll('button');
  let graph;

  startButton.addEventListener('click', async () => {
    const context = new AudioContext();
    const source = new OscillatorNode(context, { frequency: 440 });
    graph = await createVolumeGraph(context, source);
    source.start();
    startButton.disabled = true;
    stopButton.disabled = false;
  });
  stopButton.addEventListener('click', async () => {
    await graph.close();
    graph = undefined;
    startButton.disabled = false;
    stopButton.disabled = true;
  });
}

By default, worklet-processor.js, assets/effetune-dsp.wasm, assets/effetune-dsp.simd.wasm, and assets/effetune-dsp.meta.json resolve beside the mapped dist/worklet.js. If a deployment rebases them, pass processorUrl, wasmUrl, simdWasmUrl, and metaUrl in the third EffeTuneNode.create options argument; each accepts a string or URL.

The example starts a 440 Hz oscillator after a user click and routes it through a -6 dB Volume effect. Use Verification for the candidate-package browser checks.

API

EffeTuneNode.create(context, chain, options) creates the node. setParam(effectId, semanticName, value) applies an immediate update. subscribe(callback) enables decoded analyzer telemetry on the first subscriber and returns an unsubscribe function; unsubscribe(callback) removes it. Callbacks run on the node side, never inside DSP processing. droppedTelemetryFrames reports loss. reset() clears state and close() releases the worklet-side instance. Scheduled frame events belong to Python/JavaScript streams, not this Worklet API.