bitcoin-convert/lib/convert.js

Conversion between the bitcoin base unit (BTC) and other units (Satoshi, μBTC, ...)

'use strict';

const Big = require('big.js');
let units = {
    'BTC': new Big(1),
    'mBTC': new Big(0.001),
    'μBTC': new Big(0.000001),
    'bit': new Big(0.000001),
    'Satoshi': new Big(0.00000001),
    'sat': new Big(0.00000001)
};

function convert(from, fromUnit, toUnit, representation) {
    let fromFactor = units[fromUnit];
    if (fromFactor === undefined) {
        throw new Error(`'${fromUnit}' is not a bitcoin unit`);
    }
    let toFactor = units[toUnit];
    if (toFactor === undefined) {
        throw new Error(`'${toUnit}' is not a bitcoin unit`);
    }

    if (Number.isNaN(from)) {
        if (!representation || representation === 'Number') {
            return from;
        } else if (representation === 'Big') {
            return new Big(from); // throws BigError
        } else if (representation === 'String') {
            return from.toString();
        }
        throw new Error(`'${representation}' is not a valid representation`);
    }

    let result = new Big(from).times(fromFactor).div(toFactor);

    if (!representation || representation === 'Number') {
        return Number(result);
    } else if (representation === 'Big') {
        return result;
    } else if (representation === 'String') {
        return result.toString();
    }

    throw new Error(`'${representation}' is not a valid representation`);
}

convert.units = function () {
    return Object.keys(units);
};

convert.addUnit = function addUnit(unit, factor) {
    factor = new Big(factor);
    let existing = units[unit];
    if (existing && !existing.eq(factor)) {
        throw new Error(`'${unit}' already exists with a different conversion factor`);
    }
    units[unit] = factor;
};

let predefinedUnits = convert.units();
convert.removeUnit = function removeUnit(unit) {
    if (predefinedUnits.indexOf(unit) >= 0) {
        throw new Error(`'${unit}' is predefined and cannot be removed`);
    }
    delete units[unit];
};

module.exports = convert;