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loglevelnext is a modern logging library for Node.js and modern browsers, written with modern patterns and practices which provides log level mapping of the console object.

For browser use, or use in client-side applications, loglevelnext should be bundled by your preferred bundler or compiler, such as Rollup.

Getting Started

First thing's first, install the module:

npm install loglevelnext --save


Users can choose to use loglevelnext in Node.js or in the client (browser).

const log = require('loglevelnext');


Log Levels

By default loglevelnext ships supporting the following log level name-value pairs:

  TRACE: 0,
  DEBUG: 1,
  INFO: 2,
  WARN: 3,
  ERROR: 4,

Default Logger

When requiring loglevelnext in Node.js the default export will be an instance of LogLevel wrapped with some extra sugar.


Please see LogLevel for documentation of all methods and properties of every log instance, including the default instance.

trace, debug, info, warn, error

These methods correspond to the available log levels and accept parameters identical to their console counterparts. e.g.

// ... etc


Returns a new LogLevel instance. The options parameter should be an Object matching the options for the LogLevel constructor.

Note: LogLevel instances created are cached. Calling create with a previously used name will return the cached LogLevel instance. To create a different instance with the same name, assign a unique id property to the options parameter.



Type: Array [ Class ]

Returns an Array containing the factory classes available within loglevelnext to outside modules. Particularly useful when creating plugins. eg.

const log = require('loglevelnext');
const { MethodFactory } = log.factories;
class MyFactory extends MethodFactory { ... }


Type: Array [ LogLevel ]

Returns an Array containing references to the currently instantiated loggers.

Factories aka Plugins

If you're used to using plugins with loglevel, fear not. The same capabilities are available in loglevelnext, but in a much more straightforward and structured way. loglevelnext supports by way of "Factories." A Factory is nothing more than a class which defines several base methods that operate on the console and provide functionality to a LogLevel instance. All factories must inherit from the MethodFactory class, and may override any defined class functions.

For an example factory, please have a look at the PrefixFactory which provides similar functionality as the loglevel-prefix plugin, and is the factory which is used when a user passes the prefix option to a LogLevel instance.

Browser Support

As mentioned, loglevelnext is a logging library for Node.js and modern browsers, which means the latest versions of the major browsers. When bundling or compiling loglevelnext for use in a browser, you should ensure that appropriate polyfills are used. e.g. Internet Explorer typically requires polyfilling both Symbol and Object.assign.


This project originated as a fork of the much-loved loglevel module, but has diverged and has been rewritten, and now shares similarities only in functional intent.

Base Log SVG by Freepik from www.flaticon.com.



LICENSE (Mozilla Public License)

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