@smartput/speed

m/s, km/h, mph, knots.

Canonical in metres per second. The knot ratio is the full 28-digit value: 0.514444 was the true number truncated, and a wrong constant is not a smaller one.

Three doors, one table. The kind descriptor is for the engine, /validate is free functions over JS numbers, /class is an immutable value class — and all three read the same UnitTable, so a unit added once is added everywhere. See Validating without the engine.

Setup

npm add @smartput/speed

Example

import { parseSpeed, asSpeed, formatSpeed } from "@smartput/speed/validate";
import { Speed } from "@smartput/speed/class";

parseSpeed("80 kph")                         // {"ok":true,"value":80,"unit":"kph","raw":"80"}
asSpeed("80 kph", "mps")                     // {"ok":true,"value":22.22222222222222,"unit":"mps","raw":"22.22222222222222"}
formatSpeed(parseSpeed("80 kph"))            // "80kph"
String(Speed.parse("80 kph"))                // "80kph"

// …and the same table through the engine:
engine.evaluate("100 kph in mph").formatted  // "62.1371 mph"
engine.evaluate("10 knot in kph").formatted  // "18.52 km/h"
engine.evaluate("60 mph").formatted          // "60 mph"

parse and as never throw — they answer { ok: true, … } or { ok: false, code, input }. The value class throws on bad input and Speed.tryParse does not. All three read the one UnitTable below.

Entry points

| Import | Contents | | --- | --- | | @smartput/speed | The package root. | | @smartput/speed/units | The UnitTable: ratios and aliases, with no engine and no Decimal. | | @smartput/speed/validate | Free functions over JS numbers. Ok \| Err, never a throw. | | @smartput/speed/class | The immutable value class. | | @smartput/speed/locale/<id> | One language's words for this kind. 17 ship: en, de, fr, es, pt, it, nl, zh, ja, ar, ru, pl, tr, hi, ko, id, uk. |

Units

Read from the table itself, not typed out — a unit added to the source appears here on the next bun run docs:packages. Ratios are decimal strings, which is what lets the engine widen them to Decimal without a float in between.

SPEED_UNITS

| Unit | Ratio to mps | Aliases | | --- | --- | --- | | mps | 1 | mps | | kph | 0.2777777777777777777777777778 | kmh kph | | mph | 0.44704 | mph | | knot | 0.5144444444444444444444444444 | kt knot knots |

Runtime exports

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

SPEED_UNITS · speed

Dependencies

• @smartput/kind
• @smartput/shared

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 | | --- | --- | --- | | speed/validate parseSpeed only | ≤ 1.3 kB | ≤ 700 B |

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/speed.md.