Fix Morse trainer audio on mobile Safari (await AudioContext resume)#2088
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iOS Safari starts the Web Audio context suspended and resume() is async; the trainer fired resume() without awaiting it, so the first tones were scheduled against a still-suspended clock and never sounded on mobile Safari. ensureCtx now awaits resume() before returning (matching metronome.js / scorePlayback.js / songPlayback.js), and the keying decoder's startTone awaits it too (bailing on a fast release to avoid an orphan oscillator) while stopTone reads the clock off the live oscillator's context so it stays synchronous. Claude-Session: https://claude.ai/code/session_01USGJgLzYBHwis8rn38K3Pn
…phan tone - Regression test now resolves the mock resume() on a macrotask so the test actually fails if the await is removed (a microtask-resolving mock passed either way, giving false confidence). - startTone uses a generation token, not just pressingRef, so a release-then-repress during first-press resume latency can't leave two overlapping starts both creating an oscillator and orphaning the first. Claude-Session: https://claude.ai/code/session_01USGJgLzYBHwis8rn38K3Pn
Moving the resume() await earlier means prompt/playing aren't set until after the first-play iOS unlock, so the Start Round / New Round button stays live during that window. A second tap started a second overlapping playPrompt(true), scheduling two Morse prompts over each other with the UI tracking only the last. Add a synchronous playingRef re-entrancy guard to startRound/playPrompt, with a regression test asserting a double-tap in the unlock window creates only one oscillator. Claude-Session: https://claude.ai/code/session_01USGJgLzYBHwis8rn38K3Pn
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Summary
The Morse code trainer produced no sound on mobile Safari. iOS Safari starts the Web Audio
AudioContextsuspended andresume()is asynchronous — the trainer firedresume()without awaiting it, so the first tones were scheduled against a still-suspended clock and never sounded. Desktop browsers resume fast enough that the 50 ms scheduling lead hid the bug.Root cause
useAudioContext().ensureCtx()calledctx.resume()fire-and-forget, unlike every other audio module in the app (metronome.js,scorePlayback.js,songPlayback.js), which allawait c.resume()before scheduling.Changes
ensureCtxnowawaitsresume()before returning the context (Copy / Head Copy / Send all benefit).playPromptawaitsensureCtx().startToneawaitsensureCtx()and uses a generation token so a fast release-then-repress during the first-play unlock can't orphan a droning oscillator;stopTonereads the clock off the live oscillator'scontextso it stays synchronous.startRound/playPrompt: the earlier await widened the window where the Start Round button is still live during the iOS unlock, so a double-tap could schedule two overlapping prompts — now ignored.Tests
Added regression tests in
MorseTrainer.test.jsx:suspended(mock resolvesresume()on a macrotask so the test actually fails if theawaitregresses).All 18 MorseTrainer tests + 80 meatspace tests pass. Reviewed locally with claude + codex.
https://claude.ai/code/session_01USGJgLzYBHwis8rn38K3Pn