visual-logger

visual-logger

Visual CLI logger for NodeJS

This is a simple logger that combines in-place terminal updates for showing things like progress, spinners, etc.

Demo as used in fyn:

Install

npm install visual-logger

Usage

Log lines scroll normally. Items are the in-place part: each one owns a line at the bottom of the screen that you update as work progresses, and removing it leaves the scrollback clean.

import VisualLogger from "visual-logger";

const logger = new VisualLogger();

logger.info("starting");

logger.addItem({ name: "install", color: "green", display: "Installing", spinner: true });
logger.updateItem("install", "resolving dependencies");
logger.updateItem("install", { msg: "linking", display: "Linking" });
logger.removeItem("install");

logger.info("done");

API

Logging

debug(), verbose(), info(), log(), warn(), error() - one per level. Levels are debug (10), verbose (20), info (30), warn (40), error (50), fyi (60) and none (100); each gets its own color, exported as LevelColors.

prefix(str | false) and setPrefix(str) set a prefix on subsequent lines.

Items

method	description
addItem({ name, color, display, spinner, spinInterval, save })	add an in-place item; spinner may be true, a style name or index
updateItem(name, msg | { msg, display })	update what the item shows
removeItem(name)	remove it
clearItems()	remove all of them
freezeItems(showItems?) / unfreezeItems()	stop and resume in-place updating - useful around output you don't want overwritten
setItemType(type)	normal, simple, or none to turn in-place rendering off (what CI wants)

Item names may be strings or symbols.

Also exported

VisualLogger (also the default export), Levels, LevelColors, LogItemTypes, defaultOutput, and the VisualOutput / OutputInterface types for supplying your own output target.

License

Licensed under the Apache License, Version 2.0.