Logger

Example

import Logger from '@bubblehunt/logger';

// Simple
// --------------------------------------------------------
const simpleLogger = new Logger;

simpleLogger.info( 'Writes to stdout', 1, { a: [ 123 ] } );


// Full
// --------------------------------------------------------
import FileTransport from '@bubblehunt/logger/transports/FileTransport';

const logPath = __dirname + 'out';

const logger = new Logger({
    // Minimal level which would be printed.
    // Levels strictness from min to max:
    //   'trace' | 'debug' | 'info' | 'warn' | 'error' | 'fatal' | 'none'
    level: 'info',
    // Same as level but for stdout specially
    stdoutLevel: 'debug',
    // Whether to process.exit( 1 ) on fatal error
    stopOnFatal: true,
    // Log process label
    hostname: 'Main',
    // Separates each message in stdout
    stdoutMsgSeparator: '----------------------',
    // Sets or disables stdout: Logger | Transport | false
    // default: StdoutTransport
    stdout: undefined,
    // Every message will be written to transport if level matches
    transports: [
        new FileTransport({
            level: 'trace',
            // If not strict then all upper levels will also be printed
            strict: false,
            // here we explicitly set print type
            printType: 'json',
            // File will be created right away even if no data was written
            createOnFirstWrite: false,
            filePath: `${ logPath }/0_all.json`,
        }),
        new FileTransport({
            level: 'trace',
            filePath: `${ logPath }/1_trace.json`,
        }),
        new FileTransport({
            level: 'debug',
            filePath: `${ logPath }/2_debug.json`,
        }),
        new FileTransport({
            level: 'info',
            filePath: `${ logPath }/3_info.json`,
        }),
        new FileTransport({
            level: 'warn',
            filePath: `${ logPath }/4_warn.json`,
        }),
        new FileTransport({
            level: 'error',
            filePath: `${ logPath }/5_error.json`,
        }),
        new FileTransport({
            level: 'fatal',
            filePath: `${ logPath }/6_fatal.json`,
        }),
    ],
    printConfig: {
        // Whether to use colors in stdout
        colors: false,
        // Object print depth
        depth: 5,
        // First elements quantity to print
        maxArrayLength: 30,
    },
    // arguments to JSON.stringify if printType: 'json'
    jsonStringifyArgs: [],
});

logger.info( 'writes to first transport, with level "info" and to stdout' );

logger.trace( { a: 1 }, 1 ); // nothing: requires level "debug" or higher

logger.stdout.info( 'writes only to stdout' );


// Make child with new options
// --------------------------------------------------------
const logger2 =
        logger.child({
            hostname: 'Child-1',
            level: 'trace',
        });

logger2.trace( 'writes to two first transports with level "trace"' );


// Make child with new options
// --------------------------------------------------------
const logger3 =
        logger2.child({
            hostname: 'Child-2',
            stdoutLevel: 'trace',
        });

logger3.trace( 'writes to two first transports with level "trace" and to stdout' );


// Make child with new options
// --------------------------------------------------------
const logger4 =
        logger3.child({
            hostname: 'Child-3',
            level: 'error',
            stdoutLevel: 'error',
        });

logger4.info( 'no writes' );

// if "info" is ignored then "state" can be used to log smth important
logger4.state( 'writes to first transport and stdout' );

Transport

Example: create Transport

/* @flow */

// =============================================================================
// Imports
// =============================================================================
import {
    Transport,
    type TransportConfigType,
    type HandlerType,
} from '@bubblehunt/logger/transports/Transport';

// Flow types
// --------------------------------------------------------
type DefaultConfigType = {};

type MyTransportConfigType =
    & TransportConfigType
    & DefaultConfigType;


// =============================================================================
// Constants
// =============================================================================
const DefaultConfig = {
    // Required message level to call handler
    // level?: LevelType,

    // Called if current Transport class has no method 'handler'
    // handler?: HandlerType,

    // Messages format
    // printType?: 'json' | 'simple-cli' | 'simple',

    // if true ( default ) then msg will be printed only if level is equal to transport's
    // if false it is printed when level is equal or greater
    // strict?: boolean,
};


// =============================================================================
// MyTransport
// =============================================================================
export class MyTransport extends Transport<MyTransportConfigType> {

    constructor( config?: TransportConfigType ) {
        super({ ...DefaultConfig, ...config });
    }

    handler: HandlerType = ( logStr, options ) => {
        console.log( logStr, options );
    };

    end = () => {};
}

export default MyTransport;