backtrace-logging

Hide unnecessary logs¹ until an error² occurs.

Loosely based implementation of http://www.exampler.com/writing/ring-buffer.pdf

• ¹ console.debug/warn in Browser/Node, util.debug and optionally process.stdout/err in Node.
• ² window.on(error) in Browser, process.on(uncaughtException, exit) in Node.
• Auto-register for plug-n-play use, using import.meta.url query strings
• Customizable API for advanced usage

Install

npm install backtrace-logging

Usage

Just import this in NodeJS and all your console.debug and console.warn logs will be buffered (upto capacity=10) until the end (process.on(error)):

import 'backtrace-logging/node.js'

Or this in the browser with some customizations:

import 'backtrace-logging/browser.js?console=log,debug,warn&capacity=10'

API

Replace …/node.js with …/browser.js accordingly.

Core

import BacktraceLogging from 'backtrace-logging'
const bl = new BacktraceLogging(opts)

• opts.capacity [number=10] How many messages to buffer
• opts.queue [Queue] Custom queue for fn-buffer
• opts.store [Map] Custom map to store { original => patch } function pairs

---

Patch a function to buffer its calls

bl.fn(fn, opts)

• fn <function> Function to patch
• opts [object] options for fn-buffer

Example:

console.log = bl.fn(console.log)

---

Patch an object's key method with the patched function

bl.object(object, key, opts)

• object <object> Object to patch
• key <string> Key to patch in the object
• opts [object] options for fn-buffer

Example:

bl.object(console, 'log')

---

Get the original function of the patched function back

bl.get(patch)

• patch <function> The patched function

Example:

console.log = bl.get(console.log) // restored

---

Flush the queue

bl.flush()

Register Helper

?auto=false must be passed to disable auto-registration

import { register } from 'backtrace-logging/node.js?auto=false'
register(meta, opts = meta.opts)

Browser/Node

• meta.console [array=debug,warn] Keys to patch in console
• opts [object] options for fn-buffer

Node only

• meta.util [boolean] Patch util.debug
• meta.process [array] Keys to patch in process (stdout|stderr)
• meta.file [string] File to append skipped logs to

Auto Register

Requiring …/node.js without ?auto=false calls the register helper function automatically with meta options parsed from import.meta.url.

Pass the values of meta object as a URL query string.

Arrays must be passed as comma-separated values.

import 'backtrace-logging/browser.js?console=log,debug,warn&capacity=10'

Dependencies

• fn-buffer