@smartput/rate

The money kind, rate snapshots, and the live-rate facade.

Money is not in BUILTIN_KINDS and never will be: it needs an injected rate table, so it ships here and the caller registers it. snapshot() builds a dated immutable table; ecb() and custom() are providers; createLiveEngine() wraps fetch, cache, TTL and one shared in-flight request.

A rate without an asOf is a number pretending to be a fact, so every snapshot carries one.

Setup

npm add @smartput/rate

Example

import { money, snapshot, ecb } from "@smartput/rate";
import { parseAmount, symbolOf } from "@smartput/currency";

JSON.stringify(parseAmount("$12.50"))  // "{\"ok\":false,\"code\":\"nan\",\"input\":\"$12.50\"}"
symbolOf("uah")                        // "₴"
money.id                               // "money"

money is a kind whose ratios are read from a rate snapshot rather than fixed, so createLiveEngine is what turns "100 usd in eur" into an answer. ecb is the European Central Bank daily reference feed; snapshot is the offline shape it fills. Nothing here calls the network until you hand it a provider.

Entry points

| Import | Contents | | --- | --- | | @smartput/rate | The package root. | | @smartput/rate/locale/<id> | One language's words for this kind. 17 ship: en, uk, de, fr, es, pt, it, nl, zh, ja, ar, ru, pl, tr, hi, ko, id. |

Runtime exports

Type-only exports are erased and do not appear here.

CURRENCIES · createLiveEngine · custom · ecb · money · snapshot

Dependencies

• @smartput/core
• @smartput/currency
• @smartput/kind
• decimal.js

What it costs

Ceilings, not measurements. bun run check-size bundles each entry with bun build --minify and fails if a row crosses its ceiling or drops more than 30 % below it — a budget that is only an upper bound reports a vanished graph as a triumph.

| Import | Minified | Gzipped | | --- | --- | --- | | rate/locale/en (a vocabulary outside the kind packages) | ≤ 36.1 kB | ≤ 14.2 kB |

Generated by scripts/gen-readmes.ts — run bun run docs:readmes. Every output above was produced by running the line beside it. The full page, with live demos, is docs/packages/rate.md.