Unitopia

Types and utilities for associating units (dimensions) to quantities. The primary use case for Unitopia is applications that deal with like measurements in possibly non-homogenous units. For example, an application that allows the user to switch between pounds and kilograms, or tasks that can be measured in days or weeks.

What it provides:

• Type safety for working with dimensional values, making it more difficult to accidentally compare or perform arithmetic on dissimilar units.
• Ergonomic unit conversion & normalization.
• Serialization and deserialization to JSON.
• Zero dependencies.

Currently available dimensions:

• Length
• Mass (weight)
• Time

Coming soon:

• Money (currency)
• Power (Watt)
• Current (Ampere)
• Voltage (Volt)

Coming not-so-soon:

• Support for derived units & dimensional analysis

Usage

Creating Quantities

To create a quantity object, simply import the appropriate class and use the appropriate static method:

import { Mass } from 'unitopia'

const m1 = Mass.Pounds(100)
const m2 = Mass.Kilograms(22)

The type of m1 will be Mass<'Pound'>, tye type of m2 will be Mass<'Kilogram'>. You can also use the Mass constructor but (currently) it won't be typed to the specific unit:

const m3 = new Mass(2, 'Short Ton')

The type of m3 will be Mass<'Kilogram' | 'Milligram' | 'Gram' | 'Short Ton' |...>. For this reason, it's preferred to use the convenience constructors illustrated above.

Serializing Quantities

Quantities can be serialized directly with JSON.stringify:

JSON.stringify(m1) // {"dimension":"Mass","unit":"Pound","value":100}

Deserializing Quantities

Deserialize with the parse or tryParse methods, which can accept either an object or a string (which will be parsed from JSON):

try {
  const m = Mass.parse({ dimension: 'Mass', unit: 'Gram', value: 100 })
  console.log(m)
} catch (err) {
  console.error('parsing error:', err.message)
}
const res = Mass.tryParse({ dimension: 'Mass', unit: 'Gram', value: 100 })
if ('error' in res) console.error('parsing error:', err.message)
else console.log(res.mass)

Unit Conversion

Simply call the static convert method and specify the desired unit:

import { Length } from 'unitopia'
const h1 = Length.Inches(71)
const h2 = Length.convert(h1, 'Centimeter') // h2.value is 180.34000000072135

Unit Array Normalization

To normalize an array of possibly nonhomogeneous values, call the static normalize method:

const lengths = [Length.Inches(71), Length.Meters(0.5), Length.Feet(2.5)]
const lengths_in_cm = Length.normalize(length, 'Centimeter')

Contributing

TODO