@signalk/streams/dist/timestamp-throttle.js

Utilities for handling streams of Signal K data

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const moment_1 = __importDefault(require("moment"));
const stream_1 = require("stream");
function defaultGetMilliseconds(msg) {
    // 2014-08-15-16:00:00.083
    return (0, moment_1.default)(msg.timestamp, 'YYYY-MM-DD-HH:mm:ss.SSS').valueOf();
}
class TimestampThrottle extends stream_1.Transform {
    lastMsgMillis;
    offsetMillis = 0;
    getMilliseconds;
    constructor(options = {}) {
        super({ objectMode: true });
        this.lastMsgMillis = Date.now();
        this.getMilliseconds = options.getMilliseconds ?? defaultGetMilliseconds;
    }
    _transform(msg, encoding, done) {
        const msgMillis = this.getMilliseconds(msg);
        if (msgMillis < this.lastMsgMillis) {
            this.offsetMillis = Date.now() - msgMillis;
        }
        this.lastMsgMillis = msgMillis;
        const millisToCorrectSendTime = msgMillis - Date.now() + this.offsetMillis;
        if (millisToCorrectSendTime <= 0) {
            this.push(msg);
            done();
        }
        else {
            const doPush = this.push.bind(this, msg);
            setTimeout(() => {
                doPush();
                done();
            }, millisToCorrectSendTime);
        }
    }
}
exports.default = TimestampThrottle;