rxjs-obd/lib/operators/obdReader.js

RxJS Implementation for OBD (On Board Diagnostics) of vehicles via ELM 327 connections.

import { Subscriber } from 'rxjs';
var OBD_OUTPUT_MESSAGE_TYPES;
(function (OBD_OUTPUT_MESSAGE_TYPES) {
    OBD_OUTPUT_MESSAGE_TYPES["MODE_01"] = "41";
    OBD_OUTPUT_MESSAGE_TYPES["MODE_09"] = "09";
})(OBD_OUTPUT_MESSAGE_TYPES || (OBD_OUTPUT_MESSAGE_TYPES = {}));
const OBD_NO_DATA = 'NO DATA';
const OBD_PROMPT = '>';
export function obdReader() {
    return function (source) {
        return source.lift(new OBDReaderOperator());
    };
}
class OBDReaderOperator {
    call(subscriber, source) {
        return source.subscribe(new OBDReaderSubscriber(subscriber));
    }
}
class OBDReaderSubscriber extends Subscriber {
    constructor(destination) {
        super(destination);
        /**
         * Internal buffer of bytes received from OBD.
         */
        this.memento = [];
        /**
         * Internal buffer of the entire output for debug propose.
         */
        this.buffer = '';
    }
    _next(data) {
        this.buffer += data;
        if (OBDReaderSubscriber.hasPrompt(data)) {
            const bytes = this.memento;
            if (OBDReaderSubscriber.isOutput(bytes, OBD_OUTPUT_MESSAGE_TYPES.MODE_01)) {
                this.destination.next(bytes);
            }
            else if (bytes && bytes.length && bytes[0] === OBD_NO_DATA) {
                this.destination.next(bytes);
            }
            else if (this.buffer.indexOf(OBD_OUTPUT_MESSAGE_TYPES.MODE_09) === 0) {
                this.destination.next([this.buffer]);
            }
            else {
                this.destination.error(`Prompt received without data. Last call ${JSON.stringify(data)} and the entire output was ${this.buffer}`);
            }
            //clear buffers
            this.memento = [];
            this.buffer = '';
        }
        else if (data) {
            if (OBD_NO_DATA === data) {
                this.memento = [data];
            }
            else {
                const bytes = OBDReaderSubscriber.getByteGroupings(data);
                if (OBDReaderSubscriber.isOutput(bytes, OBD_OUTPUT_MESSAGE_TYPES.MODE_01)) {
                    this.memento = bytes;
                }
            }
        }
    }
    /**
     * Determines if the passed buffer/string has a prompt.
     * that indicates it has been completed.
     * @param   data the returned data.
     * @return  flag indicating if the data has a prompt.
     */
    static hasPrompt(data) {
        // Basically, we check that the a newline has started
        return data.indexOf(OBD_PROMPT) !== -1;
    }
    /**
     * Determines if the passed buffer is an output of desired mode.
     * @param bytes the buffer returned by OBD
     * @param mode the desired mode.
     * @returns Flag indicating that is a valid result.
     */
    static isOutput(bytes, mode) {
        return bytes && bytes.length && bytes[0] === mode;
    }
    /**
     * Convert the returned bytes into their pairs if possible, or return null.
     * @param  str the returned bytes.
     * @return the returned bytes into their pairs if possible, or return null.
     */
    static getByteGroupings(str) {
        // Remove white space (if any exists) and get byte groups as pairs
        return str.replace(/ /g, '').match(/.{1,2}/g);
    }
}
//# sourceMappingURL=obdReader.js.map