@orkestrel/rater

A typed quantitative rating layer over @orkestrel/reason: authored lines — each a plain reason QuantitativeDefinition joined to display metadata — are rated against a subject (a plain data record) to produce a LineResult per line (an amount plus its Worksheet audit trail) and one RatingResult (every line's outcome plus a derived total). The caller decides which lines to rate; Rater only evaluates what it is given. Rating never mutates its inputs — every result is a fresh object. Environment-agnostic — no I/O, no browser or server assumptions. Part of the @orkestrel line.

Install

npm install @orkestrel/rater

Requirements

• Node.js >= 24
• ESM (import) and CommonJS (require) via the exports field

Usage

import { createRater, lineDefinition } from '@orkestrel/rater'
import { factorGroup, quantitativeDefinition, staticFactor } from '@orkestrel/reason'

const rater = createRater()

const base = lineDefinition(
	'base',
	'Base Amount',
	quantitativeDefinition('base', 'Base', [
		factorGroup('amount', 'sum', [staticFactor('flat', 100)]),
	]),
)

const result = rater.rate([base], { id: 'subject-1' })
result.lines[0]?.amount // 100
result.total // 100

rater.emitter.on('rate', (subject, rated) => rated.success)

rater.destroy()

rate accepts a plain LineDefinition[] or a full RatingDefinition plus one subject — both overloads rate a single subject. Every rate call fires once through rater.emitter (rate).

Guide

For the full surface — Rater, RatingResult, worksheet types, validators, factories, errors, and options — see guides/src/rater.md.

Package

Published as a single typed entry point per the exports field in package.json.

License

MIT © Orkestrel — see LICENSE.