ads-b/dist/ADSBVersion2Decoder.js

Library for decoding ADS-B messages emitted from Aircraft

"use strict";
/**
 * MIT License
 * Copyright (c) 2019 Matt Laver
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://github.com/mattlaver/ads-b/blob/master/LICENSE
 */
Object.defineProperty(exports, "__esModule", { value: true });
var crc24_1 = require("./lib/crc24");
var MessageBuilder_1 = require("./messageDecoders/MessageBuilder");
var IMessage_1 = require("./messages/IMessage");
var ADSBVersion2Decoder = /** @class */ (function () {
    function ADSBVersion2Decoder() {
        this._messageBuilder = new MessageBuilder_1.MessageBuilder();
        this.dataLinkFormat = function (byte) { return (byte >> 3) & 0x1f; };
        this.capability = function (byte) { return byte & 0x7; };
    }
    ADSBVersion2Decoder.prototype.isValid = function (message) {
        // check it looks like a ADS-B V2 message
        return message.length === 28;
    };
    ADSBVersion2Decoder.prototype.decode = function (message) {
        var firstByte = parseInt(message.substr(0, 2), 16);
        var data = message.substr(8, 14);
        var typeCode = (parseInt(data.substr(0, 2), 16) >> 3) & 0x1f;
        if (crc24_1.crc(message.substr(0, 22)) !== message.substr(22, 6)) {
            return {
                messageType: IMessage_1.MessageType.ChecksumFailed,
                raw: message,
            };
        }
        var messageDecoded = this._messageBuilder.messageFromTypeCode(typeCode, data);
        return {
            ca: this.capability(firstByte),
            data: messageDecoded.data,
            df: this.dataLinkFormat(firstByte),
            icao: message.substr(2, 6),
            messageType: messageDecoded.messageType,
            pi: message.substr(22, 6),
            raw: message,
            tc: typeCode,
        };
    };
    return ADSBVersion2Decoder;
}());
exports.ADSBVersion2Decoder = ADSBVersion2Decoder;