maths/conversions.js

/**
 * Converting between different units mostly imperial -> metric and metric -> imperial
 * @module
 */
import { unit_conversions } from './constants';
import { roundToDP } from './util';
/**
 * Convert from miles to kilometers
 * @param {number} quantity
 * @param {boolean} equivalence - if true, return value so that 1mile = 1km
 * @returns {number} kilometers to 5 decimal places
 */
const milesToKM = (quantity, equivalence = false) => {
    let num_value;
    if (equivalence) {
        // when equivalence is set to true, convert down so that 1mile = 1km
        // e.g 100 co2gpm will become  co2gpkm to accommodate the smaller
        // distance of km vs miles
        // eslint-disable-next-line
        num_value = kmToMiles(quantity);
    } else {
        num_value = quantity * unit_conversions.milesToKm;
    }
    return roundToDP(num_value, 5);
};
/**
 * Convert from kilometers to miles
 * @param {number} quantity
 * @param {boolean} equivalence - if true, return value so that 1km = 1mile
 * @returns {number} miles to 5 decimal places
 */
const kmToMiles = (quantity, equivalence = false) => {
    let num_value;
    if (equivalence) {
        // when equivalence is set to true, convert up so that 1km = 1mile
        // e.g 150 co2gpkm will become 241.401 co2gpm to accommodate the larger
        // distance of km vs miles
        num_value = milesToKM(quantity);
    } else {
        num_value = quantity * (1 / unit_conversions.milesToKm);
    }
    return roundToDP(num_value, 5);
};
/**
 * Convert from miles per gallon to litres per 100km
 * @param {number} quantity
 * @returns {number} litres per 100km
 */
const mpgToL100km = (quantity) => (1 / quantity) * unit_conversions.mpgToL100km;
/**
 * Convert from litres per 100km to miles per gallon
 * @param {number} quantity
 * @returns {number} miles per gallon
 */
const l100kmToMpg = (quantity) => (1 / quantity) * unit_conversions.mpgToL100km;
/**
 * Convert from gallons to litres
 * @param {number} quantity
 * @returns {number} litres
 */
const gallonsToLitres = (quantity) => quantity * unit_conversions.gallonsToLitres;
/**
 * Convert from litres to gallons
 * @param {number} quantity
 * @returns {number} gallons
 */
const litresToGallons = (quantity, equivalence = false) => {
    let num_value;
    if (equivalence) {
        num_value = gallonsToLitres(quantity);
    } else {
        num_value = quantity * (1 / unit_conversions.gallonsToLitres);
    }
    return roundToDP(num_value, 6);
};
/**
 * Grams per km to grams per miles
 * @param {number} quantity
 * @returns {number} gallons
 */
const gramsPerKMtoGramsPerMiles = (quantity) => {
    const num_value = quantity / (1 / unit_conversions.milesToKm);
    return roundToDP(num_value, 6);
};
const litresToHydrogenKg = (value) => value * unit_conversions.hydrogenKgToLitres;
/**
 * Hydrogen kg to litres
 * @param {number} value hydrogen in kg
 * @returns {number} converted to litres
 */
const hydrogenKgToLitres = (value, equivalence = false) => {
    let num_value;
    if (equivalence) {
        num_value = litresToHydrogenKg(value);
    } else {
        num_value = value * (1 / unit_conversions.hydrogenKgToLitres);
    }
    return roundToDP(num_value, 6);
};
export {
    milesToKM,
    kmToMiles,
    mpgToL100km,
    l100kmToMpg,
    gallonsToLitres,
    litresToGallons,
    gramsPerKMtoGramsPerMiles,
    hydrogenKgToLitres,
};