console-fmt-cli

Elegant, colorized console logging for Node.js — with optional decimal-format-core formatters for prediction-market and trading bots.

Version 2.9.0 is the recommended latest release: everything from 2.8.x plus re-exported stake and currency helpers so bot repos can depend on a single package.

npm install console-fmt-cli

Install

npm install console-fmt-cli
# peer (optional but recommended for trading bots):
npm install decimal-format-core

Node.js 14+. decimal-format-core is loaded as a peer-style optional dependency — if missing, logger functions still work; formatters throw a clear require error.

Quick start

const { createLogger } = require('console-fmt-cli');

const log = createLogger('polymarket-bot', {
  level: process.env.LOG_LEVEL || 'info',
  timestamps: true,
  child: true,
  time: true,
});

const strategy = log.child('strategy');
strategy.info('started');

Trading / stake formatting (2.9.0)

Re-exports from decimal-format-core:

const {
  createLogger,
  computeBoundedFraction,
  computeKellyStake,   // alias
  formatCurrency,
  formatStakeUsd,      // alias
  roundDecimal,
  roundStake,          // alias
} = require('console-fmt-cli');

const log = createLogger('stake', { timestamps: true });

const stake = computeKellyStake({
  probability: 0.58,
  allInPrice: 0.52,
  bankroll: 2000,
  maxStake: 100,
  scaleFactor: 0.5,
});

log.info(`size $${formatStakeUsd(stake)} (${roundStake(stake)} raw)`);

Logger API

createLogger(name, options?)

| Option | Default | Description | |--------|---------|-------------| | level | 'info' | Minimum level | | timestamps | false | ISO-8601 prefix | | color | true | ANSI colors | | prefix | true | [name] tag | | json | false | Adds log.json(obj) | | child | false | Adds log.child(sub) | | time | false | Adds log.time(label) |

Methods

log.debug(...args);
log.info(...args);
log.warn(...args);
log.error(...args);
log.json({ structured: true });     // when json: true
log.child('module');                // when child: true
const end = log.time('operation');  // when time: true
end();

Recommended bot log.js wrapper

const { createLogger } = require('console-fmt-cli');

let root;

function getLogger(module) {
  if (!root) {
    root = createLogger('bot', {
      level: process.env.LOG_LEVEL || 'info',
      timestamps: true,
      child: true,
      time: process.env.LOG_TIME === '1',
      color: process.stdout.isTTY,
    });
  }
  return module ? root.child(module) : root;
}

module.exports = { getLogger };

Why one dependency?

Trading templates previously imported:

• a CLI logger
• a stake math package
• duplicate rounding helpers

2.9.0 consolidates the common path: console-fmt-cli + optional decimal-format-core matches what open Polymarket bot scaffolds expect.

Version history

| Version | Highlights | |---------|------------| | 2.0.0 | Initial logger | | 2.2.0 | JSON lines | | 2.3.0 | Child loggers | | 2.8.0 | Timers | | 2.9.0 | decimal-format-core formatters, npm latest |

FAQ

Must I install decimal-format-core?
Only if you use formatCurrency, computeKellyStake, etc. Logging alone does not require it.

Pino / Winston?
Use this for developer-facing CLI output; pipe JSON logs from log.json() into your collector if needed.

License

MIT