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Measurements and conversions for JavaScript. Supports angle, area, duration, energy, illuminance, length, mass, power, pressure, speed, temperature, volume and generic amounts.

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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 , 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

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Measurements and conversions for JavaScript. Supports angle, area, duration, energy, illuminance, length, mass, power, pressure, speed, temperature, volume and generic amounts.

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