ts-opaque-units

ts-opaque-units

Small TypeScript opaque measurement library

Install

yarn add ts-opaque-units typescript@^4.0.0

Opaque types

For now, only time units are available:

• Milliseconds
• Seconds
• Minutes
• Hours
• Days
• Weeks
• Months
• Years
• Decades
• Centuries
• Millenniums

You are not allowed to assign variables of different types, so you are safe ✅

let hours = 1 as Hours;
let twoHours = 2 as Hours;
let minutes = 1 as Minutes;
let twoMinutes = 2 as Minutes;

/* Cannot assign different types */

// @ts-expect-error
hours = minutes;
// @ts-expect-error
minutes = hours;

/** Can assign the same types */

// ✅
minutes = twoMinutes;
hours = twoHours;

Convert

To transform one type to another safely, use a function convert:

import { convert, Minutes, Years } from "ts-opaque-units";

const minutesInHour = 60 as Minutes;
const secondsInHour = convert(minutesInHour, "minutes", "seconds");

const year = 1 as Years;
const secondsInYear = convert(year, "years", "seconds");