`hooks/use-rpn`

(no submodules)

Purpose

useRPN(selector) wraps the universal RPN reducer and exposes the consolidated RPNChange as React state. RPN ("Registered Parameter Number") covers the well-known parameters such as pitch-bend range, fine/coarse tuning, channel pressure sensitivity, and modulation depth. Like NRPN it arrives over the wire as a four-CC dance — CC 101 (param MSB), CC 100 (param LSB), CC 6 (data MSB), CC 38 (data LSB) — and the hook folds that into one React event per dance.

Features

Folds CC 101/100/6/38 into one RPNChange per dance.
Per-port reducer — fresh state on port identity change.
Returns null until the first completed dance.

Usage: Basic

import { useRPN } from "@suaveplan/react-midi";

function PitchBendRange() {
    const change = useRPN("first");
    // RPN (0,0) is "Pitch Bend Sensitivity".
    if (!change) return <p>(no RPN yet)</p>;
    return (
        <p>
            RPN ({change.paramHigh}.{change.paramLow}) → {change.value}
        </p>
    );
}

Usage: Advanced

function useChannelTuning() {
    const change = useRPN("first");
    // RPN (0,1) = fine-tuning; RPN (0,2) = coarse-tuning.
    return change?.paramHigh === 0 ? change : null;
}

API Reference

useRPN(selector: string | "first"): RPNChange | null

Implementation Notes

The hook mirrors useNRPN exactly, replacing only the reducer class and the parameter-MSB CC numbers (101 instead of 99). The reducer's data-MSB/LSB CCs (6 and 38) are shared with NRPN — devices follow the convention of sending a fresh paramHigh selector to switch between the two address spaces, which the reducer handles via its "new paramHigh resets partial state" rule. Consumers that need to listen to both NRPN and RPN streams from the same port simply compose the two hooks side by side; the underlying input adapter fans the parsed messages out to both subscriptions without double-binding the Web MIDI onmidimessage slot.

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hooks/use-rpn