thingtalk-units

   

A small library to convert and normalize between measurement units. This library
is used by the ThingTalk language to support measurements.

The library converts to and from _base units_ of various supported types, and various
additional units for each base unit.

Usage

``javascript
const TTUnits = require('thingtalk-units');
`

API

$3

Convert a unit name to the base unit, which is a standard unit for the same property.
This method throws if the unit is invalid.
Example:

`javascript
TTUnits.normalizeUnit('F') === 'C'
TTUnits.normalizeUnit('km') === 'm'
`

$3

Convert the value value, expressed in the unit unit, in the same amount in the corresponding
base unit.
Example:

`javascript
TTUnits.transformToBaseUnit(1, 'km') === 1000
`

$3

Convert the value value, expressed in the base unit, to the unit unit.
This is the inverse operation to transformToBaseUnit().
Example:

`javascript
TTUnits.transformToBaseUnit(1000, 'km') === 1
`

$3

The list of the supported base units.

Supported Units

$3

* ms: time (milliseconds)
* m: distance (meters)
* mps: speed (meters per second)
* kg: mass (kilograms)
* Pa: pressure (Pascal)
* C: temperature (Celsius)
* kcal: energy (kilocalories)
* byte: data size (Byte)
* W: power (Watt)
* lm: luminous flux (lumen)
* lx: illuminance (lux)

The choice of base units is mostly historical. Some units follow SI convention (mps, kg, Pa),
some follow common usage (kcal, C).

$3

| Unit | Base Unit | Physical quantity |
| --------------------------------- | --------- | ----------------- |
| s (seconds) | ms | time |
| min (minutes) | ms | time |
| h (hours) | ms | time |
| day (days) | ms | time |
| week (weeks) | ms | time |
| mon (business month = 30 days) | ms | time |
| year (business year = 365 days) | ms | time |
| km (kilometers) | m | distance |
| mm (millimeters) | m | distance |
| cm (centimeters) | m | distance |
| mi (miles) | m | distance |
| in (inches) | m | distance |
| kmph (kilometers per hour) | mps | speed |
| mph (miles per hour) | mps | speed |
| g (grams) | kg | mass |
| lb (US pound) | kg | mass |
| oz (US ounce) | kg | mass |
| bar (bar) | Pa | pressure |
| psi (pounds per square inch) | Pa | pressure |
| mmHg (millimeters of mercury) | Pa | pressure |
| inHg (inches of mercury) | Pa | pressure |
| F (Fahrenheit) | C | temperature |
| K (Kelvin) | C | temperature |
| kJ (kilojoule) | kcal | energy |
| KB (kilobyte) | byte | data size |
| KiB (kibibyte) | byte | data size |
| MB (megabyte) | byte | data size |
| MiB (mebibyte) | byte | data size |
| GB (gigabyte) | byte | data size |
| GiB (gibibyte) | byte | data size |
| TB (terabyte) | byte | data size |
| TiB (tebibyte) | byte | data size |
| kW (kilowatt) | W` | power |