Index / Lessons / DataTree

Chapter 7 of 9

DataTree

Presets are one JSON blob per appName — not keyed KV pushes. Native pages defer DataTree init and gate apply on a successful emit.

Native-specific rules

1. Defer init ~600 ms (not 80 ms).
2. Apply only when wax.didEmit() is true, or retry ~150 ms.
3. Applying updates JS variables used by renderGraph(), then re-renders the graph — not DOM-only.
4. Boot defaults + poke schedule run before pull/apply.

Collect / apply sketch

function collect() {
  return { schema: 1, params: { cutoffHz, q, master } };
}

function apply(raw) {
  const p = (raw && raw.params) || raw;
  if (!p) return;
  cutoffHz = p.cutoffHz ?? cutoffHz;
  q = p.q ?? q;
  master = p.master ?? master;
  syncUIFromVars();
  renderGraph();
}

async function initDataTree() {
  const helper = window.WaxWeb ? WaxWeb.create({ appName: APP_NAME }) : null;
  const dt = helper ? helper.data : window.WAX_DataTree;
  // … pull, onHydrated, push(collect()) when canPush
}

setTimeout(initDataTree, 600);

Wrong vs right

• Wrong: push("cutoff", 1200) — Right: push({ schema: 1, params: { cutoffHz: 1200 } })
• Wrong: JS envelope → wax.const amp — Right: midinotein + adsr

Full DataTree rules (Web + Native): WEB.md and NATIVE.md preset sections.

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