How to use js-quantities - 10 common examples
To help you get started, we’ve selected a few js-quantities examples, based on popular ways it is used in public projects.
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DefinitelyTyped / DefinitelyTyped / js-quantities / js-quantities-tests.ts View on Github 
it("should convert value", () => {
// TODO Same test but with m/h -> ft/s triggers rounding issue
// (For the sake of speed, converter does not check and fix rounding issues)
const converter = Qty.swiftConverter("m/h", "m/s");
expect(converter(2500)).toEqual(Qty("2500 m/h").to("m/s").scalar);
});it("should convert temperatures to temperature degrees", () => {
// according to ruby-units, temp -> deg conversion always uses the 0 relative degrees
let qty = Qty("100 tempC");
expect(qty.to("degC").scalar).toBe(100);
qty = Qty("0 tempK");
expect(qty.to("degC").scalar).toBe(0);
qty = Qty("0 tempF");
expect(qty.to("degK").scalar).toBe(0);
qty = Qty("18 tempF");
expect(qty.to("degC").scalar).toBe(10);
qty = Qty("10 tempC");
expect(qty.to("degF").scalar).toBe(18);
});it("should divide while trying to avoid numerical errors", () => {
expect(Qty.divSafe(0.000773, 0.000001)).toBe(773);
// TODO uncomment and fix
// expect(Qty.divSafe(24.5, 0.2777777777777778)).toBe(88.2);
});
});it("should divide while trying to avoid numerical errors", () => {
expect(Qty.divSafe(0.000773, 0.000001)).toBe(773);
// TODO uncomment and fix
// expect(Qty.divSafe(24.5, 0.2777777777777778)).toBe(88.2);
});
});Qty('100 tempC').div(qty); // throws error
Qty('100 tempC*unit'); // throws error
Qty('100 tempC/unit'); // throws error
Qty('100 unit/tempC'); // throws error
Qty('100 tempC').inverse(); // throws error
Qty('100 tempC').to('degC'); // => 100 degC
Qty('100 degC').to('tempC'); // => -173.15 tempC
Qty('0 tempC').add('100 degC'); // => 100 tempC
try {
// code triggering an error inside JS-quantities
} catch (e) {
if (e instanceof Qty.Error) {
// ...
} else {
// ...
}
}
// From project spec
describe("js-quantities", () => {
"use strict";
describe("initialization", () => {
it("should create unit only", () => {
const qty = Qty("m");
expect(qty.numerator).toEqual(["<meter>"]);
expect(qty.scalar).toBe(1);</meter>Qty('100 tempC').div(qty); // throws error
Qty('100 tempC*unit'); // throws error
Qty('100 tempC/unit'); // throws error
Qty('100 unit/tempC'); // throws error
Qty('100 tempC').inverse(); // throws error
Qty('100 tempC').to('degC'); // => 100 degC
Qty('100 degC').to('tempC'); // => -173.15 tempC
Qty('0 tempC').add('100 degC'); // => 100 tempC
try {
// code triggering an error inside JS-quantities
} catch (e) {
if (e instanceof Qty.Error) {
// ...
} else {
// ...
}
}
// From project spec
describe("js-quantities", () => {
"use strict";
describe("initialization", () => {
it("should create unit only", () => {
const qty = Qty("m");
expect(qty.numerator).toEqual(["<meter>"]);
expect(qty.scalar).toBe(1);</meter>qty = Qty('1 m^2/s^2');
qty = Qty('1 m^2 s^-2'); // negative powers
qty = Qty('1 m2 s-2'); // ^ is optional
qty = Qty('1 m^2 kg^2 J^2/s^2 A');
qty = Qty('1.5'); // unitless quantity
qty = Qty(1.5); // number as initializing value
qty = Qty('1 attoparsec/microfortnight');
let qtyCopy: Qty;
qtyCopy = Qty(qty); // quantity could be copied when used as initializing value
Qty.parse('1 m'); // => 1 meter
Qty.parse('foo'); // => null
Qty.getKinds(); // => Array of names of every well-known kind of units
Qty.getUnits('currency'); // => [ 'dollar', 'cents' ]
// Or all alphabetically sorted
Qty.getUnits(); // => [ 'acre','Ah','ampere','AMU','angstrom']
Qty.getAliases('m'); // => [ 'm', 'meter', 'meters', 'metre', 'metres' ]
const qty1 = Qty('1m');
const qty2 = Qty('2m');
qty1.isCompatible(qty2); // => true or false
qty.kind(); // => 'length', 'area', etc...qty = Qty('1 m^2/s^2');
qty = Qty('1 m^2 s^-2'); // negative powers
qty = Qty('1 m2 s-2'); // ^ is optional
qty = Qty('1 m^2 kg^2 J^2/s^2 A');
qty = Qty('1.5'); // unitless quantity
qty = Qty(1.5); // number as initializing value
qty = Qty('1 attoparsec/microfortnight');
let qtyCopy: Qty;
qtyCopy = Qty(qty); // quantity could be copied when used as initializing value
Qty.parse('1 m'); // => 1 meter
Qty.parse('foo'); // => null
Qty.getKinds(); // => Array of names of every well-known kind of units
Qty.getUnits('currency'); // => [ 'dollar', 'cents' ]
// Or all alphabetically sorted
Qty.getUnits(); // => [ 'acre','Ah','ampere','AMU','angstrom']
Qty.getAliases('m'); // => [ 'm', 'meter', 'meters', 'metre', 'metres' ]
const qty1 = Qty('1m');
const qty2 = Qty('2m');
qty1.isCompatible(qty2); // => true or false
qty.kind(); // => 'length', 'area', etc...qty = Qty(1.5); // number as initializing value
qty = Qty('1 attoparsec/microfortnight');
let qtyCopy: Qty;
qtyCopy = Qty(qty); // quantity could be copied when used as initializing value
Qty.parse('1 m'); // => 1 meter
Qty.parse('foo'); // => null
Qty.getKinds(); // => Array of names of every well-known kind of units
Qty.getUnits('currency'); // => [ 'dollar', 'cents' ]
// Or all alphabetically sorted
Qty.getUnits(); // => [ 'acre','Ah','ampere','AMU','angstrom']
Qty.getAliases('m'); // => [ 'm', 'meter', 'meters', 'metre', 'metres' ]
const qty1 = Qty('1m');
const qty2 = Qty('2m');
qty1.isCompatible(qty2); // => true or false
qty.kind(); // => 'length', 'area', etc...
qty.isUnitless(); // => true or false
qty.isBase(); // => true if quantity is represented with base units
qty.toBase(); // converts to SI units (10 cm => 0.1 m) (new instance)
qty.toFloat(); // returns scalar of unitless quantity (otherwise throws error)qty = Qty('1.5'); // unitless quantity
qty = Qty(1.5); // number as initializing value
qty = Qty('1 attoparsec/microfortnight');
let qtyCopy: Qty;
qtyCopy = Qty(qty); // quantity could be copied when used as initializing value
Qty.parse('1 m'); // => 1 meter
Qty.parse('foo'); // => null
Qty.getKinds(); // => Array of names of every well-known kind of units
Qty.getUnits('currency'); // => [ 'dollar', 'cents' ]
// Or all alphabetically sorted
Qty.getUnits(); // => [ 'acre','Ah','ampere','AMU','angstrom']
Qty.getAliases('m'); // => [ 'm', 'meter', 'meters', 'metre', 'metres' ]
const qty1 = Qty('1m');
const qty2 = Qty('2m');
qty1.isCompatible(qty2); // => true or false
qty.kind(); // => 'length', 'area', etc...
qty.isUnitless(); // => true or false
qty.isBase(); // => true if quantity is represented with base units
qty.toBase(); // converts to SI units (10 cm => 0.1 m) (new instance)js-quantities
JavaScript library for quantity calculation and unit conversion
