Amounts

Represent amounts of stuff with units and conversions. Supports lenient parsing of amounts, normalization and basic formatting.

const { length, duration } = require('amounts');
 
// Supports parsing from strings:
const value = length('30 m');
// Convert into another unit (returns a number)
console.log(length.as('ft'));
console.log(length.feet);
 
// Parse durations
console.log(duration('20 m, 4 s'));
 
// Supports precision on the numbers
length('2.8 cm')
length('2e10 m')

Amounts tries to be friendly with handling input, supporting variations of units, such as both short and long names, with longer unit names being case insensitive.

These will all parse to the same unit and value:

mass('750 ug');
mass('750 micrograms');
mass('750 micro gram');
mass('750 MikroGram')

But this will not work:

mass('750 uG');

Or fetch units from factories and use convert:

// To convert to mmHg
pressure.unit('mmHg').convert('200.12 kPa');
// Or back to kPa
pressure.unit('kPa').convert(1501.023, 'mmHg');

API

All amounts that can be represented share a common API. Factories support:

• factory(string)

  Parse the given string into an amount.

• factory(value, unit)

  Create an amount with the given value and unit.

• factory(value)

  Create an amount with the given value and the default unit.

• factory.unit(unit)

  Get a unit that can be used for conversions for this factory.

Instances have the following API:

• amount.value: Number

  Get the value of the amount.

• amount.unit: String

  Get the unit of the amount.

• amount.as(unit): Number

  Convert the amount to the given unit and return the result as a number.

• amount.to(unit): Amount

  Convert the amount into another unit and return an object with the value.

Every amount also exposes getters for the most commonly used units:

length('20 cm').meters
length('19 ft').cm
 
volume(1, 'l').oz

Generic amounts

The generic amount does not have any units, but supports SI-prefixes.

const { generic } = require('amounts');
 
// Without any unit, returns an amount with value 20
console.log(generic(20));
 
// With a generic SI-unit, returns an amount with value 20000
console.log(generic('20k'));
 
// Full length names are supported
console.log(generic('20 micro'))

SI-prefixes

Units in the SI system can be combined with SI-prefixes to create a new unit. SI-prefixes are supported both by their short names and their long names. Examples: cm, milliliters, hPa, MW, kilowatt

Long Name	Short name	Factor	Factor (expanded)
yocto	y	10-24	0.000 000 000 000 000 000 000 001
zepto	z	10-21	0.000 000 000 000 000 000 001
atto	a	10-18	0.000 000 000 000 000 001
femto	f	10-15	0.000 000 000 000 001
pico	p	10-12	0.000 000 000 001
nano	n	10-9	0.000 000 001
micro	u, mc, µ	10-6	0.000 001
milli	m	10-3	0.001
centi	c	10-2	0.01
deci	d	10-1	0.1
deca, deka	da	101	10
hecto	h	102	100
kilo	k	103	1 000
mega	M	106	1 000 000
giga	G	109	1 000 000 000
tera	T	1012	1 000 000 000 000
peta	P	1015	1 000 000 000 000 000
exa	E	1018	1 000 000 000 000 000 000
zetta	Z	1021	1 000 000 000 000 000 000 000
yotta	Y	1024	1 000 000 000 000 000 000 000 000

Angle

const { angle } = require('amounts');
 
console.log(angle(2, 'rad'));
console.log(angle('5 degrees').as('radians'));

Unit	SI	Names
Degree	No	deg, degree, degrees
Radian	Yes	rad, radian, radians

Area

const { area } = require('amounts');
 
console.log(area(2, 'm^2'));
console.log(area('10 sq ft').as('m2'));

Unit	SI	Names
Square Meter	Yes	m², m^2, m2, square metre, square metres, square meter, square meters
Square Inch	No	sq in, square inch, square inches
Square Foot	No	sq ft, square foot, square feet
Square Yard	No	sq yd, square yard, square yards
Square Mile	No	sq mi, square mile, square miles
Hectare	No	ha, hectare, hectares
Acre	No	acre, acres

Duration

Durations represent a number of milliseconds something takes. Multiple units can be combined into a value.

const { duration } = require('amounts');
 
console.log(duration(2000)); // Defaults to milliseconds
console.log(duration('1d'));
console.log(duration('2h 10m'));
console.log(duration('2 days, 5 hours'));

Unit	SI	Names
Milliseconds	No	ms, millisecond, milliseconds
Seconds	No	s, second, seconds
Minutes	No	m, minute, minutes
Hours	No	h, hour, hours
Days	No	d, day, days

Energy

const { energy } = require('amounts');
 
console.log(energy(10)); // Joules
console.log(energy('3.5 kJ').kWh);

Unit	SI	Names
Joules	Yes	J, j, joule, joules
Watt hours	True	Wh, wh, watt hour, watt hours

Illuminance

const { illuminance } = require('amounts');
 
console.log(illuminance(2, 'lx'));
console.log(angle('8000 lux'));

Unit	SI	Names
Lux	Yes	lx, lux
Phot	No	ph, phot
Nox	No	nx, nox
Foot-candle	No	fc, lm/ft², ft-c, foot-candle, foot-candles, foot candle, foot candles

Length

const { length } = require('amounts');
 
console.log(length(2)); // Meters
console.log(length('5 ft').as('micrometer'));
console.log(length('2 ft ').cm);

Unit	SI	Names
Metre	Yes	m, meter, meters, metre, metres
Inch	No	in, inch, inches
Feet	No	ft, foot, feet
Yard	No	yd, yard, yards
Mile	No	mi, mile, miles

Mass

const { mass } = require('amounts');
 
console.log(mass(210)); // Grams
console.log(mass('78 kg').lbs);
console.log(mass('2 stone').kg)

Unit	SI	Names
Gram	Yes	g, gram, grams, gramme, grammes
Pound	No	lb, lbs, pound, pounds, #
Ounce	No	oz, ounce, ounces
Stone	No	st, stone, stones

Power

const { power } = require('amounts');
 
console.log(power(500)); // Watts
console.log(power('6000 kW').mW);
console.log(power('6 hp').as('microwatts'));

Unit	SI	Names
Watt	Yes	w, W, watt
Horsepower	No	hp, horsepower

Pressure

const { pressure } = require('amounts');
 
console.log(pressure(500)); // Pascal
console.log(power('700 hPa').atm);
console.log(power('7 bar').kPa);

Unit	SI	Names
Pascal	Yes	pa, Pa, pascal, pascals
Atmosphere	No	atm, atmosphere, atmospheres
Bar	No	bar, bars
PSI	No	psi, pounds per square inch, pound per square inch
Torr	No	torr
mmHg	No	mmHg, 'millimetre of mercury', millimetres of mercury, millimeter of mercury, millimetres of mercury

Sound Pressure Level

const { soundPressureLevel } = require('amounts');
 
console.log(soundPressureLevel(30)); // db
console.log(soundPressureLevel(30, 'dB')); // db

Unit	SI	Names
Decibels	No	dB, db, dbs, decibel, decibels

Speed

const { speed } = require('amounts');
 
console.log(speed(500)); // m/s
console.log(speed('5 km/s').kph);
console.log(speed('10 mph').mps);

Unit	SI	Names
Metres/Second	Yes	m/s, mps, metre per second, metres per second, meter per second, meters per second, metre/second, metres/second, meter/second, meters/second
Kilometre/Hour	No	km/h, kph, kilometre per hour, kilometres per hour, kilometer per hour kilometers per hour, kilometers/hour, kilometre/hour
Miles/Hour	No	mph, mile per hour, miles per hour, mile/hour, miles/hour
Feet/Second	No	ft/s, fps, foot per second, feet per second, foot/second, feet/second
Knot	No	kt, knot, knots

Temperature

const { temperature } = require('amounts');
 
console.log(temperature(22)); // Celsius
console.log(temperature('200 K').celsius);
console.log(temperature(80, 'f').kelvin);

Unit	SI	Names
Celsius	No	C, c, celsius
Kelvin	Yes	K, kelvin, kelvins
Fahrenheit	No	F, f, fahrenheit, fahrenheits

Voltage

const { voltage } = require('amounts');
 
console.log(voltage(22)); // Volts
console.log(voltage('200 V').volts);

Unit	SI	Names
Volt	Yes	V, v, volt, volts

Volume

const { volume } = require('amounts');
 
console.log(volume(2)); // Liters
console.log(volume(2, 'quarts').dl);
console.log(volume('20 ml').tbsp);

Unit	SI	Names
Liter	Yes	l, L, liter, litre, litre, litres
Gallon	No	gal, gallon, gallons
Quart	No	qt, quart, quarts
Pint	No	pt, pint, pints
Cup	No	cu, cup, cups
Fluid ounce	No	floz, oz, fluid ounce, ounce, fluid ounces, ounces
Tablespoon	No	tb, tbsp, tbs, tablesppon, tablespoons
Teaspoon	No	tsp, teaspoon, teaspoons