Simple module that capture errors and log it. Works both server and browser.

Installation

Node.js

npm install katch --save

Add in top of your entry point app

Basic usage

// detect automatically all errors
require('katch')();
// others modules

Browser

Add before others scripts

Local

<script src="node_modules/katch/dist/katch.min.js"></script>
<script>katch()</script>

CDN unpkg

<script src="https://unpkg.com/katch/dist/katch.min.js"></script>
<script>katch()</script>

CDN jsDeliver

<script src="https://cdn.jsdelivr.net/npm/katch/dist/katch.min.js"></script>
<script>katch()</script>

Examples

const katch = require('katch');

const config = {
    // works only in server environment, in browser store to localStorage
    writeFile: {
        folderPath: './errors'
    }
};

katch(config);

// events

katch.on('error', (error, params) => {
    console.log(error, params);
});

Log format

{"level":"ERROR","code":102,"message":"ReferenceError: func4 is not defined... ecc...ecc...","params":{"custom":"horror"},"time":"2017-08-06 13:39:41","hash":"0bc33304126ab9051e585f931074175597e8fb6f5e721f23f4e9804d42c32173","host":"Zallo","pid":9972,"platform":"win32"}
{"level":"INFO","code":104,"message":"info message","params":{},"time":"2017-08-06 22:19:13","hash":"86677fb54af6bb0d646af35ae56afe35275290c046959a27ecce3171f680b61e","host":"Zallo","pid":9344,"platform":"win32"}
{"level":"WARN","code":103,"message":"wanr message","params":{},"time":"2017-08-06 22:19:13","hash":"ffb322974b101dc063ca0b150e4d2a817ce0e58e362bac149caf0791018c0171","host":"Zallo","pid":9344,"platform":"win32"}
{"level":"DEBUG","code":105,"message":"debug message","params":{},"time":"2017-08-06 22:19:13","hash":"dbb69a4d04a33f4b13f90dd3a068d9c358d33f210a98e3c07e27a24f3dfe7d51","host":"Zallo","pid":9344,"platform":"win32"}
{"level":"TRACE","code":106,"message":"Trace: trace message... ecc...ecc...","params":{},"time":"2017-08-06 22:19:13","hash":"7a2625faa021efb2a6a9a7fcd4ccbef26c40e98cd400938775248abb12ebd8df","host":"Zallo","pid":9344,"platform":"win32"}

Log archive

• Server
  • The log files are saved by default in the logs folder with the file name of the current day
• Browser
  • The log are saved in localStorage with key name katch

Capture manually

const katch = require('katch');

katch.setup({
    writeFile: false
});

try {
    foo();
    bar();
} catch (e) {
    katch.log.error(e, {
        customParam: 'hello horror'
    });
}

//... or using a wrap method

katch.wrap(() => {
    foo();
    bar();
}, {
    customParam: 'hello horror'
});

katch.on('error', (error, params) => {
    console.log(error, params);
});

Append to log

Katch was created to capture all the errors in an app but can also be used as a logger

// Info
katch.log.info('A log message', {custom: 1234});

katch.on('info', (message, params) => {
    console.log(message, params);
});

// Debug
katch.log.debug('A debug message', {custom: 1234});

katch.on('debug', (message, params) => {
    console.log(message, params);
});

// Warn
katch.log.warn('A log message', {custom: 1234});

katch.on('warn', (message, params) => {
    console.log(message, params);
});

// Fatal
katch.log.fatal('A log message', {custom: 1234});

katch.on('fatal', (message, params) => {
    console.log(message, params);
});

// Error
katch.log.error(new Error('my error'), {custom: 1234});

katch.on('error', (error, params) => {
    console.log(error, params);
});

// Trace
katch.log.trace('trace', {custom: 1234});

katch.on('trace', (trace, params) => {
    console.log(trace, params);
});

Log levels

Name	Code
FATAL	101
ERROR	102
WARN	103
INFO	104
DEBUG	105
TRACE	106

Add custom level

katch.addLevel('MYLEVEL', '123');
katch.log.MYLEVEL('hello level', {myParams: 'wow'});
katch.on('MYLEVEL', (message) => {
    console.log(message);
});

Remove custom level

katch.removeLevel('MYLEVEL');

Log event

Every invoked

katch.on('log', obj => {
    console.log(obj);
    // obj
    { 
        time: '2017-08-02 19:01:46',
        level: 'INFO', // INFO, WARN, FATAL, ERROR, DEBUG, ...custom
        code: 104,
        hash: 'b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9',
        message: 'hello world',
        params: { foo: 'bar' },
        host: 'DEVELOP-STATION', // only server
        pid: 22232, // only server
        platform: 'win32' // only server,
        useragent: '"Mozilla/5.0...' // only browser
     }
     
});

Catch error from Koa and Express

• Koa

  const app = new Koa();
  katch.from.koa(app);
  app.use(ctx => {
    throw new Error('koa error');
  });

• Express

  const app = require('express')();
  app.get('/', function (req, res) {
      throw new Error('express error');
  });
  // after all routes
  app.use(katch.from.express);

Configuration

const config = {
    console: true, // outputs in console
    logging: true, // if false disable writing log. The event "log" will be invoked anyway 
    writeFile: { // only server environment
        prefix: '', // add a prefix to filename
        humanize: true, // write a readable log
        folderPath: './logs' // folder path
    }
}

Changelog

You can view the changelog here

License

katch is open-sourced software licensed under the MIT license

Author

Fabio Ricali