@jbroll/nmea-simple/codecs/HDM.ts

NMEA 0183 sentence parser and encoder

/*
 * === HDM - Heading - magnetic ===
 *
 * ------------------------------------------------------------------------------
 *        1   2 3
 *        |   | |
 * $--HDM,x.x,M*hh<CR><LF>
 * ------------------------------------------------------------------------------
 *
 * Field Number:
 * 1. Heading degrees, magnetic
 * 2. M = Magnetic
 * 3. Checksum
 */


import { createNmeaChecksumFooter, encodeFixed, parseFloatSafe } from "../helpers";
import { initStubFields, PacketStub } from "./PacketStub";


export const sentenceId: "HDM" = "HDM";
export const sentenceName = "Heading - magnetic";


export interface HDMPacket extends PacketStub<typeof sentenceId> {
    heading: number;
}


export function decodeSentence(stub: PacketStub, fields: string[]): HDMPacket {
    return {
        ...initStubFields(stub, sentenceId, sentenceName),
        heading: parseFloatSafe(fields[1])
    };
}


export function encodePacket(packet: HDMPacket, talker: string): string {
    const result = ["$" + talker + sentenceId];

    result.push(encodeFixed(packet.heading, 1));
    result.push("M");

    const resultWithoutChecksum = result.join(",");
    return resultWithoutChecksum + createNmeaChecksumFooter(resultWithoutChecksum);
}