v0.19.0 - Pan and reverse

[danigb]

0.19.0

Pan

Stereo panning is now built into every instrument's output channel. Set it at construction time or at runtime:

const drums = new DrumMachine(context, { pan: -0.5 }); // slightly left
drums.output.pan = 0.8; // right
drums.output.pan = 0; // centre

pan accepts a value from -1 (full left) to +1 (full right). Default is 0 (centre).

Probabilistic steps (chance on SequencerNote)

Add a chance field (0–100, default 100) to any sequencer note. The probability is re-rolled on every loop pass:

seq.addTrack(drums, [
  { note: "kick", at: "1:1" },
  { note: "hihat", at: "1:1", chance: 50 }, // fires ~50 % of the time
  { note: "hihat", at: "1:3", chance: 75 },
]);

Reverse playback

Play a sample backwards by setting reverse: true on a note event:

drums.start({ note: "cymbal", reverse: true });

The reversed buffer is created lazily on first use and cached — subsequent calls reuse it with no extra allocation.

Step event on Sequencer

sequencer.on("step", (stepIndex, time) => ...) fires at each grid subdivision. Enable it with the stepSize constructor option:

const seq = new Sequencer(context, {
  bpm: 120,
  loop: true,
  stepSize: "16n",
});

seq.on("step", (stepIndex, time) => {
  const delay = (time - context.currentTime) * 1000;
  setTimeout(() => ui.highlightStep(stepIndex % 16), delay);
});

Minor Changes

• Export Smplr class and all core types (SmplrJson, SmplrGroup, SmplrRegion, PlaybackParams, etc.) from the package root. Rename sequencer's NoteEvent to SequencerNoteEvent to avoid the name collision.