Cashify 💸
Lightweight currency conversion library, successor of money.js
- Motivation
- Highlights
- Install
- Usage
- API
- Migrating from money.js
- Floating point issues
- Related projects
- License
Motivation
This package was created, because the popular money.js library:
- is not maintained (last commit was ~5 years ago)
- has over 20 open issues
- does not support TypeScript
- has implicit globals
- does not have any unit tests
- has floating point issues
Highlights
- Simple API
- 0 dependencies
- Actively maintained
- Well tested
- Easy migration from money.js
- Written in TypeScript
Install
$ npm install cashify
Usage
With constructor
const {Cashify} = require('cashify');
const rates = {
GBP: 0.92,
EUR: 1.00,
USD: 1.12
};
const cashify = new Cashify({base: 'EUR', rates});
const result = cashify.convert(10, {from: 'EUR', to: 'GBP'});
console.log(result); //=> 9.2
Without constructor
Using the Cashify
constructor is not required. Instead, you can just use the convert
function:
const {convert} = require('cashify');
const rates = {
GBP: 0.92,
EUR: 1.00,
USD: 1.12
};
const result = convert(10, {from: 'EUR', to: 'GBP', base: 'EUR', rates});
console.log(result); //=> 9.2
Parsing
Cashify supports parsing, so you can pass a string
to the amount
argument and the from
and/or to
currency will be automatically detected:
const {Cashify} = require('cashify');
const rates = {
GBP: 0.92,
EUR: 1.00,
USD: 1.12
};
const cashify = new Cashify({base: 'EUR', rates});
// Basic parsing
cashify.convert('€10 EUR', {to: 'GBP'});
// Full parsing
cashify.convert('10 EUR to GBP');
Alternatively, if you just want to parse a string
without conversion, you can use the parse
function, which returns an object
with parsing results:
const {parse} = require('cashify');
parse('10 EUR to GBP'); //=> {amount: 10, from: 'EUR', to: 'GBP'}
Note: If you want to use full parsing, you need to pass a string
with specific format:
10 usd to pln
12.5 GBP in EUR
3.1415 eur as chf
You can use to
, in
or as
to separate the expression (case insensitive). Used currencies name case doesn't matter, as cashify will automatically convert them to upper case.
currency.js
Integration withcurrency.js is a small and lightweight library for working with currency values. It works great with cashify. In the following example we are using it to format the conversion result:
const {Cashify} = require('cashify');
const currency = require('currency.js');
const rates = {
GBP: 0.92,
EUR: 1.00,
USD: 1.12
};
const cashify = new Cashify({base: 'EUR', rates});
const converted = cashify.convert(8635619, {from: 'EUR', to: 'GBP'}); // => 7944769.48
// Format the conversion result
currency(converted, {symbol: '€', formatWithSymbol: true}).format(); // => €7,944,769.48
API
Cashify({base, rates})
Constructor
base
Type: string
Base currency
rates
Type: object
Object containing currency rates (for example from an API, such as Open Exchange Rates)
with and without constructor
convert(amount, {from, to, base, rates}) Returns conversion result (number
)
amount
Type: number
or string
Amount of money you want to convert. You can either use a number
or a string
. If you choose the second option, you can take advantage of parsing and not specify from
and/or to
argument(s).
from
Type: string
Currency from which you want to convert. You might not need to specify it if you are using parsing.
to
Type: string
Currency to which you want to convert. You might not need to specify it if you are using parsing.
base
Type: string
Base currency
rates
Type: object
Object containing currency rates (for example from an API, such as Open Exchange Rates)
parse(expression)
Returns an object
, which contains parsing results:
{
amount: number;
from: string | undefined;
to: string | undefined;
}
expression
Type: string
Expression you want to parse, ex. 10 usd to pln
or €1.23 eur
Migrating from money.js
With Cashify
constructor:
- const fx = require('money');
+ const {Cashify} = require('cashify');
- fx.base = 'EUR';
- fx.rates = {
- GBP: 0.92,
- EUR: 1.00,
- USD: 1.12
- };
+ const rates = {
+ GBP: 0.92,
+ EUR: 1.00,
+ USD: 1.12
+ };
+ const cashify = new Cashify({base: 'EUR', rates});
- fx.convert(10, {from: 'GBP', to: 'EUR'});
+ cashify.convert(10, {from: 'GBP', to: 'EUR'});
With convert
function:
- const fx = require('money');
+ const {convert} = require('cashify');
- fx.base = 'EUR';
- fx.rates = {
- GBP: 0.92,
- EUR: 1.00,
- USD: 1.12
- };
+ const rates = {
+ GBP: 0.92,
+ EUR: 1.00,
+ USD: 1.12
+ };
- fx.convert(10, {from: 'GBP', to: 'EUR'});
+ convert(10, {from: 'GBP', to: 'EUR', base: 'EUR', rates});
Floating point issues
When working with currencies, decimals only need to be precise up to the smallest cent value while avoiding common floating point errors when performing basic arithmetic.
Let's take a look at the following example:
const fx = require('money');
const {Cashify} = require('cashify');
const rates = {
GBP: 0.92,
USD: 1.12
};
fx.rates = rates;
fx.base = 'EUR';
const cashify = new Cashify({base: 'EUR', rates});
fx.convert(10, {from: 'EUR', to: 'GBP'}); //=> 9.200000000000001
cashify.convert(10, {from: 'EUR', to: 'GBP'}); //=> 9.2
As you can see, money.js doesn't handle currencies correctly and therefore a floating point issues are occuring. Even though there's just a minor discrepancy between the results, if you're converting large amounts, that can add up.
Cashify solves this problem the same way as currency.js - by working with integers behind the scenes. This should be okay for most reasonable values of currencies.
Related projects
- currency.js - Lightweight javascript library for working with currency values.
- cashify-rs - Cashify port for Rust.
License
MIT © Antoni Kepinski