Convert & format

Convert between units with exact legal factors (temperature deltas included), then render values back with best-fit and compound output. Everything format() emits re-parses to the same value.

import { convert, convertDelta, tryConvert, quantity } from "@pascal-app/lingo"

convert(72, "in", "ft")            // 6            (exact legal factors)
convert(1, "gal", "L")             // 3.785411784
convertDelta(5, "C", "F")          // 9            (a difference, not 41)

const targetUnit: string = "cm"    // a dynamic ref (the escape hatch)
tryConvert(5, "kg", targetUnit)    // { ok: false, issues } instead of throwing

quantity(1500, "m").toBest().format()                    // "1.5 km"
quantity(1.8034, "m").format({ compound: ["ft", "in"] }) // "5′11″"
quantity(2, "ft").format({ style: "long" })              // "2 feet"

convert throws on a bad pair; tryConvert returns a structured issue instead. convertDelta converts a difference — a 5 °C rise is a 9 °F rise, not 41.

Typeset the reading

A result keeps the unit id and the numeric value in separate fields, so rendering notation is a pure mapping over the result — m/s2 becomes a fraction with a superscript, ± tolerance becomes an interval. lingo ships no renderer; the docs site maps results to LaTeX for KaTeX in about ninety lines.