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zerg
TypeScript icon, indicating that this package has built-in type declarations

2.1.2 • Public • Published

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Zerg

Lightweight logging library for apps and libs

Futures

  • Zero dependencies
  • TypeScript support
  • Easy to use
  • Custom listeners/transports
  • Support Node.js and Browsers

Getting started

Installation

npm i --save zerg

or

yarn add zerg

Usage

Make module logger.js:

import zerg from 'zerg';
import {
  consoleNodeColorful,
  consoleBrowserColorful,
} from 'zerg/dist/transports';
 
const logger = zerg.createLogger();
 
// Add console logger
const listener = zerg.createListener({
  handler: consoleBrowserColorful, // for browser
  // handler: consoleNodeColorful, // for node
});
 
logger.addListener(listener);
 
export default logger;

Make your module and import logger.js:

import logger from './logger';
 
const log = logger('moduleName');
 
log.verbose('verbose message');
log.debug('debug message');
log.info('info message');
log.warn('warn message');
log.error('error message', {foo: 'bar'});

Result:

ScreenShot

API

Types

type TExtendedData = Record<string, any>;

type TLogMessage = {
  timestamp: number;
  loggerName: string;
  moduleName: string;
  level: TLogLevel;
  message: string;
  extendedData?: TExtendedData
};

type LogLevel = 'verbose' | 'debug' | 'info' | 'warn' | 'error';

type Listener = (log: TLogMessage) => void;

zerg.createLogger(): Logger - Create logger instance

zerg.createListener(params): LogListener - Create listener for logger

  • params.handler: (logMessage: TLogMessage) => void;
  • params.filter?: (logMessage: TLogMessage) => boolean; (optional)
  • params.levels?: LogLevel; (optional)

logger.addListener(listener: LogListener)

import zerg from 'zerg';
 
const logger = zerg.createLogger();
 
const listener = zerg.createListener({
  handler: (logMessage) => console.log(logMessage),
  levels: ['info'], // listen only `info` level
});
 
logger.addListener(listener);
 
logger.module('myModule').info('Info message', {foo: 'bar'});
logger.module('myModule').warn('Warn message', {bar: 'baz'});
logger.module('myModule').error('Error message');
 
/* console
{
  timestamp: 1467967421933,
  level: 'info',
  moduleName: 'myModule',
  message: 'Info message',
  extendedData: {foo: 'bar'},
}
*/

Use filter - Listen messages only from "Sarah" module

import zerg from 'zerg';
 
const logger = zerg.createLogger();
 
const listener = zerg.createListener({
  handler: (logMessage) => console.log(logMessage),
  filter: (logMessage) => logMessage.moduleName === 'Sarah', // listen messages only from "Sarah" module
  // levels: [], // at this case levels are ignoring
});
 
logger.addListener(listener);
 
logger.module('Alice').info('Info message', {foo: 'bar'});
logger.module('Bob').warn('Warn message', {bar: 'baz'});
logger.module('Sarah').error('Error message');
 
/* console
{
  timestamp: 1467967421933,
  level: 'info',
  moduleName: 'myModule',
  message: 'Info message',
  extendedData: {foo: 'bar'},
}
*/

removeListener(LogListener): void;

removeAllListeners(): void;

module(moduleName: string): LoggerModule;

getModule(moduleName: string): LoggerModule | null;

getModules(): Record<string, LoggerModule>;

Other Examples

Sentry transport

import zerg from 'zerg';
const logger = zerg.createLogger();
 
const SENTRY_LEVEL_MAP = {
  info: 'info',
  warn: 'warning',
  error: 'error',
  fatal: 'error',
};
 
function sentryTransport(logMessage) {
  const level = SENTRY_LEVEL_MAP[logMessage.level];
 
  Sentry.withScope((scope) => {
    scope.setLevel(level);
 
    Object.keys(logMessage.extendedData).forEach((key) => {
      scope.setExtra(key, logMessage.extendedData[key]);
    });
 
    scope.setTag('module', logMessage.moduleName);
 
    Sentry.captureMessage(logMessage.message);
  });
}
 
const listener = zerg.createListener({handler: sentryTransport});
 
logger.addListener(listener);

Remote debug transport

It is be useful for debug when browser (or device) doesn't provide tool: Android with default browser, WinPhone, SmartTV.

At browser:

import zerg from 'zerg';
const logger = zerg.createLogger();
 
function remoteTransport(logMessage) {
  const req = new XMLHttpRequest();
  req.open('POST', 'http://myhost.com:3000/log', false);
  req.setRequestHeader('Content-type', 'application/json');
  req.send(JSON.stringify(logMessage));
}
 
const listener = zerg.createListener({handler: remoteTransport});
 
logger.addListener(listener);

Don't forget, host (http://myhost.com:3000/log) must be reachable from device.

At server you may use express:

const express = require('express');
const bodyParser = require('body-parser');
 
const app = express();
app.use(bodyParser.json()); // for parsing application/json
 
app.post('/log', (req, res) => {
  console.log(req.body);
});
 
app.listen(3000);

Readme

Keywords

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Install

npm i zerg

Repository

github.com/ahiipsa/zerg

Homepage

github.com/ahiipsa/zerg#readme

Weekly Downloads

89

Version

2.1.2

License

MIT

Unpacked Size

28.6 kB

Total Files

33

Last publish

Collaborators

  • ahiipsa
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