log-capture

A lightweight JavaScript library for intercepting browser console methods. My first npm package 😅☺️

Installation

pnpm add log-capture

Or with npm:

npm install log-capture

Quick Start

import { capture } from 'log-capture'

capture.on('log', (original, ...args) => {
    // Handle the intercepted log
    original(...args)
})

capture.start()

console.log('Hello world')

The original console methods are preserved and can be called through the original function provided to each listener.

Use Cases

log-capture can be used as a foundation for different console-related features, such as:

• Remote logging — send browser logs and errors to a remote server for monitoring and debugging.
• Visual console — display console messages directly inside the application's DOM, useful for dashboards, development tools, and embedded applications.
• Hide logs — prevent selected logs, warnings, or errors from being displayed in the browser console.
• Log filtering — filter messages based on their method, content, or custom application rules.
• Error monitoring — collect errors and warnings and send them to an external monitoring service.
• Custom logging — transform or process console messages before passing them to the original console method.

Supported Methods

log-capture currently intercepts:

• log
• warn
• table
• clear
• debug
• error

Listening to Console Methods

Use on() to add one or more listeners.

capture.on('error', (original, ...args) => {
    saveError(args)

    original(...args)
})

Multiple listeners can be registered for the same method:

capture.on('log', listener1, listener2)

Important

Do not call an intercepted console method inside a listener:

// Do not do this
capture.on('log', (...args) => {
    console.log(...args)
})

This can cause an infinite interception loop.

If you want to keep the original console behavior, use the original function:

capture.on('log', (original, ...args) => {
    saveLog(args)

    original(...args)
})

Removing Listeners

Use off() to remove specific listeners:

const handleError = (original, ...args) => {
    saveError(args)
    original(...args)
}

capture.on('error', handleError)

capture.off('error', handleError)

To remove all listeners for a method:

capture.off('error')

Start and Stop

Start interception with start():

capture.start()

Stop interception with stop():

capture.stop()

When stopped, the original console methods are restored.

EventListener Aliases

addEventListener() and removeEventListener() are aliases for on() and off().

capture.addEventListener('warn', handleWarning)

capture.removeEventListener('warn', handleWarning)

Checking the Capture State

Use isCapturing to check whether interception is active:

if (capture.isCapturing) {
    // Capture is active
}

Registered listeners are available through listeners:

console.log(capture.listeners)

License

MIT

Enjoy, peace and love 😇✌️☺️​