TelegramAppender - for log4js-node
Pre-requisites:
- registered a telegram bot
 - telegram bot token
 - put the bot in a chat group
 - chat id of the group
 - reference: Telegram Bot API
 
Install peer dependency log4js:
npm install --save log4js
Install log4js-node-telegramAppender:
npm install --save "https://github.com/liangwp/log4js-node-telegramAppender/tarball/master"
Sample usage:
'use strict';
const log4js = require("log4js");
log4js.configure({
    appenders: {
        colouredConsole: { type: 'stdout' },
        telegramAlert: {
            type: 'log4js-node-telegramAppender',
            silentAlertLevel: 'info',
            audioAlertLevel: 'error',
            bottoken: <token>,
            botchatid: <chatid>
        }
    },
    categories: { default: { appenders: ['colouredConsole', 'telegramAlert'], level: 'debug' } }
})
var logger = log4js.getLogger("TEST");
logger.debug(`This logs to console only`);
logger.info(`This logs to console and telegram, without telegram notification sound`);
logger.error(`This logs to console and telegram, with telegram notification sound`);