Logby

A minimal TypeScript logger inspired by logback

Introduction

Logby is a TypeScript logger inspired by logger solutions from the Java world like logback and slf4j. Usable in both browser or Node.js based environments.

Docs

Usage

npm install logby

Each logger instance is part of a Logby instance. The Logby instance handles caching of logger instances, the appender-queue and the active log level. The logger instances do the actual logging for a class.

In most cases, you want one Logby instance for your application, and multiple loggers from that for the different components and classes of your application.

import { Logby, Levels } from "logby";

const logby = new Logby();

class Foo {
    private static readonly logger = logby.getLogger(Foo);

    constructor() {
        Foo.logger.info("Hello World!");

        logby.level = Levels.ERROR;

        Foo.logger.info("You can't see me.");
    }
}

Appenders

Appenders can be attached and detached from Logby instances:

import { Logby, ILevel, defaultLoggingAppender } from "logby";

const logby = new Logby();

/*
 * Detach the built-in appender and attach our own.
 */
logby.appenders.delete(defaultLoggingAppender);
logby.appenders.add((level: ILevel, name: string, args: any[]) =>
    console.log(args)
);

class Foo {
    private static readonly logger = logby.getLogger(Foo);

    constructor() {
        Foo.logger.info("Hello World!");
    }
}

Built-in appenders

defaultLoggingAppender

Regular appender simply creating and logging a log entry.

delegatingAppender

Appender which delegates all invocations to the specified other logby instance. To create a new delegatingAppender, use the exported createDelegatingAppender(target) function.

Built-in Levels