consola

What is consola?

The consola npm package is a console logger for Node.js and browsers. It provides an easy-to-use API for logging information, warnings, errors, and more, with a focus on developer experience and universal compatibility.

What are consola's main functionalities?

Basic Logging

Consola allows you to log messages at various levels, such as info, warn, and error, which are color-coded and formatted for better readability.

const consola = require('consola');
consola.info('Information message');
consola.warn('Warning message');
consola.error('Error message');

Reporters

You can add custom reporters to modify how logs are displayed or processed, giving you control over the logging output.

const consola = require('consola');
consola.addReporter({
  log(logObj) {
    console.log(logObj.message);
  }
});

Tagged Logging

Consola supports tagged logging, which allows you to prepend a tag to your log messages, making it easier to filter and identify logs related to specific parts of your application.

const consola = require('consola').withTag('my-tag');
consola.info('Tagged information message');

Log Level Control

You can control the log level threshold, which determines the minimum level of logs that will be displayed, allowing you to filter out less important logs in different environments.

const consola = require('consola');
consola.level = 3; // Only display logs with a level of 3 (errors) or higher

Other packages similar to consola

winston

Winston is a multi-transport async logging library for Node.js. It is similar to consola in that it provides logging capabilities, but it also allows for more complex transport configurations, such as logging to files, databases, or remote services.

pino

Pino is a very low overhead Node.js logger, which focuses on performance. It provides similar logging capabilities to consola but is designed to be as efficient as possible, making it suitable for high-performance applications.

debug

Debug is a tiny Node.js debugging utility that is similar to consola's tagged logging feature. It allows you to create debug instances with different namespaces, which you can enable or disable using environment variables.

log4js

Log4js is a logging framework for Node.js, which provides similar functionality to consola. It supports multiple appenders, log levels, and layouts, and it can be configured via JSON configuration files.

README

Consola

Elegant Console Logger for Node.js and Browser

Why Consola?

👌  Easy to use
💅  Fancy output with fallback for minimal environments
🔌  Pluggable reporters
💻  Consistent command line interface (CLI) experience
🏷  Tag support
🚏  Redirect console and stdout/stderr to consola and easily restore redirect.
🌐  Browser support
⏯  Pause/Resume support
👻  Mocking support
👮‍♂️  Spam prevention by throttling logs

Installation

Using yarn:

yarn add consola

Using npm:

npm i consola

Getting Started

const consola = require('consola')

// See types section for all available types

consola.success('Built!')
consola.info('Reporter: Some info')
consola.error(new Error('Foo'))

Will display in the terminal:

NOTE: Alternatively, you can import consola from source. But don't forget to whitelist it for transpilation:

import consola from 'consola/src/node'
import consola from 'consola/src/browser'

Methods

<type>(logObject) <type>(args...)

Log to all reporters.

Example: consola.info('Message')

A list of available types can be found here.

addReporter(reporter)

• Aliases: add

Register a custom reporter instance.

removeReporter(reporter?)

• Aliases: remove, clear

Remove a registered reporter.

If no arguments are passed all reporters will be removed.

setReporters(reporter|reporter[])

Replace all reporters.

create(options)

Create a new Consola instance and inherit all parent options for defaults.

withDefaults(defaults)

Create a new Consola instance with provided defaults

withTag(tag)

• Aliases: withScope

Create a new Consola instance with that tag.

wrapConsole() restoreConsole()

Globally redirect all console.log, etc calls to consola handlers.

wrapStd() restoreStd()

Globally redirect all stdout/stderr outputs to consola.

wrapAll() restoreAll()

Wrap both, std and console.

console uses std in the underlying so calling wrapStd redirects console too. Benefit of this function is that things like console.info will be correctly redirected to the corresponding type.

pauseLogs() resumeLogs()

• Aliases: pause/resume

Globally pause and resume logs.

Consola will enqueue all logs when paused and then sends them to the reported when resumed.

mockTypes

• Aliases: mock

Mock all types. Useful for using with tests.

The first argument passed to mockTypes should be a callback function accepting (typeName, type) and returning the mocked value:

consola.mockTypes((typeName, type) => jest.fn())

Please note that with the example above, everything is mocked independently for each type. If you need one mocked fn create it outside:

const fn = jest.fn()
consola.mockTypes(() => fn)

If callback function returns a falsy value, that type won't be mocked.

For example if you just need to mock consola.fatal:

consola.mockTypes((typeName) => typeName === 'fatal' && jest.fn())

NOTE: Any instance of consola that inherits the mocked instance, will apply provided callback again. This way, mocking works for withTag scoped loggers without need to extra efforts.

Fields

reporters

An array of active reporters.

level

The level to display logs. Any logs at or above this level will be displayed. List of available levels here.

You can set the log level using the CONSOLA_LEVEL environment variable, which must have the numeric log level as its value.

logObject

The logObject is a free-to-extend object which will be passed to reporters.

Standard fields:

• message
• additional
• args
• date
• tag

Extra fields:

• badge

Reporters

Choose between one of the built-in reporters or bring in your own one.

By default FancyReporter is registered for modern terminals or BasicReporter will be used if running in limited environments such as CIs.

Available reporters:

• BasicReporter
• FancyReporter
• JSONReporter
• WinstonReporter

Creating your own reporter

A reporter (class or object) exposes log(logObj) method. To get more info about how to write your own reporter, take a look into the linked implementations above.

Types

Types are used to actually log messages to the reporters. Each type is attached to a logging level.

A list of all available default types is here.

Creating a new instance

Consola has a global instance and is recommended to use everywhere. In case more control is needed, create a new instance.

import consola from 'consola'

const logger = consola.create({
    // level: 4,
    reporters: [
      new consola.JSONReporter()
    ],
    defaults: {
      additionalColor: 'white'
    }
})

Integrations

With jest

describe('your-consola-mock-test', () => {
  beforeAll(() => {
      // Redirect std and console to consola too
      // Calling this once is sufficient
      consola.wrapAll()
    })

    beforeEach(() => {
      // Re-mock consola before each test call to remove
      // calls from before
      consola.mockTypes(() => jest.fn())
    })


  test('your test', async () => {
    // Some code here

    // Let's retrieve all messages of `consola.log`
    // Get the mock and map all calls to their first argument
    const consolaMessages = consola.log.mock.calls.map(c => c[0])
    expect(consolaMessages).toContain('your message')
  })

})

With jsdom

{
  virtualConsole: new jsdom.VirtualConsole().sendTo(consola)
}

License

MIT - Made with 💖 By Nuxt.js team!