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

NMEA 0183 sentence parser and encoder

/*
 * === MTK - Configuration packet ===
 *
 * ------------------------------------------------------------------------------
 *       1   2 ... n n+1
 *       |   |     | |
 * $--MTKxxx,a,...,a*hh<CR><LF>
 * ------------------------------------------------------------------------------
 *
 * Field Number:
 * 1. Packet type (000-999)
 * 2. - n. Data fields; meaning and quantity vary depending on the packet type
 * n+1. Checksum
 */


import { createNmeaChecksumFooter, padLeft, parseIntSafe, parseNumberOrString } from "../helpers";
import { initStubFields, PacketStub } from "./PacketStub";


export const sentenceId: "MTK" = "MTK";
export const sentenceName = "Configuration packet";


export interface MTKPacket extends PacketStub<typeof sentenceId> {
    packetType: number;
    data: (string | number)[];
}


export function decodeSentence(stub: PacketStub, fields: string[]): MTKPacket {
    return {
        ...initStubFields(stub, sentenceId, sentenceName),
        packetType: parseIntSafe(stub.sentenceId.substr(3)),
        data: fields.slice(1).map<string|number>(parseNumberOrString)
    };
}


export function encodePacket(packet: MTKPacket, talker: string): string {
    let result = ["$" + talker + sentenceId + padLeft(packet.packetType, 3, "0")];

    result = result.concat(packet.data.toString());

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