pretty-money

A tiny currency formatting library for JavaScript.

• Small. Dependency-free. 471 bytes minified and gzipped. Controlled by Size Limit.
• Functional. The function is automatically curried (think Ramda).
• Flexible. It can be tweaked to present any modern currency.

import prettyMoney from "pretty-money";
let price = prettyMoney({ currency: "EUR" }, 10000); //=> "10000 EUR"

Works in any ES3-compatible environment, be that Node.js or a browser. Try it yourself!

Install

pretty-money is available on NPM, so you can install it your usual way:

npm install pretty-money
# or 
yarn add pretty-money

If you only need to use pretty-money on the client side, you can install the latest version with jsDelivr:

<script src="https://cdn.jsdelivr.net/npm/pretty-money@1.0/dist/pretty-money.umd.js"></script>

Usage

There are two ways to use pretty-money: traditional and functional.

Traditional way is to call the function with two parameters: the config object and the number you need to format:

const prettyDollarConfig = {
    currency: "$",
    position: "before",
    spaced: false,
    thousandsDelimiter: ","
}
 
const priceA = prettyMoney(prettyDollarConfig, 1234); //=> "$1,234"
const priceB = prettyMoney(prettyDollarConfig, 567.89); //=> "$567.89"

Functional way is to curry the function, i.e. to create a function with a set config and to later call it with only one parameter — the number to format:

const prettyEuro = prettyMoney({
    currency: "€",
    decimals: "fixed",
    decimalDelimiter: ",",
    thousandsDelimiter: "."
})
 
const priceA = prettyEuro(1234); //=> "1.234,00 €"
const priceB = prettyEuro(567.89); //=> "567,89 €"

You can read more about the available configuration parameters in the next section, Config.

Config

currency

Type: string
Default: ""

The string to be used as currency symbol.
It can be a respective sign (like "$"), currency code (like "GBP") or a word (like "peso").

decimalDelimiter

Type: string
Default: "."

A string that separates the integer and the fraction parts of the number.

maxDecimal

Type: number
Default: 2

The maximum number of decimal places allowed in the number.

minDecimal

Type: number
Default: 0

The minimum number of decimal places allowed in the number. Has no effect when decimals is set to "fixed".

decimals

Type: string
Values: "fixed", "fluid" or "minmax"
Default: "minmax"

Sets the strategy to calculate the amount of decimal places.

• "fixed" — the amount of places will always stay at maxDecimal. minDecimal has no effect.
• "fluid" — the amount of places will stay at any number between minDecimal and maxDecimal, in order not to have trailing zeros.
• "minmax" — the amount of places will stay at maxDecimal unless it's possible to be at minDecimal without having trailing zeros.

position

Type: string
Values: "before" or "after"
Default: "after"

Sets the position of the currency symbol with respect to the number.

spaced

Type: boolean
Default: true

Sets whether there should be a space between the number and the currency symbol.

thousandsDelimiter

Type: string
Default: ""

A string that separates the thousands of the number.

Difference from toLocaleString

ECMAScript's Number has a method toLocaleString, which has a similar idea. It too can be used to format numbers as financial values and it even has a lot of built-in locales. However, the output of it is different on different Node.js versions and browsers:

let price = (10000).toLocaleString("ru", {
    style: "currency",
    currency: "RUB"
});
 
console.log(price);
//=> "10 000,00 ₽"    in modern browsers
//=> "RUB 10,000.00"  in Node v12.13.0
//=> "RUB 10,000"     in Node v4.8.6

This can lead to unexpected output and difficulties in debugging.

While pretty-money doesn't have any locales built-in, it provides a flexible API, so that the end user can compose any currency formatting function they need.

let price = prettyMoney({
    currency: "₽",
    thousandsDelimiter: " "
}, 10000);
 
console.log(price);
//=> "10 000 ₽"       in every Node, in every browser

Development

If you want to improve pretty-money, create your own fork of it or just play around with the developer build, here's all you need to know:

• npm run dev to start a dev server, which will automatically build the library after you change the source and output it to ./dist/pretty-money.dev.js
• npm run build to build the production-ready minified version of the library and output it to ./dist/pretty-money.umd.js and ./dist/pretty-money.esm.js
• npm run test to build the project and run all tests, which include:
  • npm run test:lint to check the code formatting with ESLint (this won't auto fix errors)
  • npm run test:unit to run the Jest unit tests
  • npm run test:size to check the size

There are no peer dependencies and other extra requirements. Any help is welcome when it keeps things simple and small.