npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

decimalize

v1.1.1

Published

JS decimal expressions library written in TypeScript

Downloads

1

Readme

Decimalize

A JS decimal expressions library written in TypeScript

Allows you to write easily readable arithmetic expressions using more precise decimal types

const difference = (x, y) => dec`${x} - ${y}`;

Available from NPM

npm install decimalize

 

Numbers in JavaScript

Have you ever tried running 0.1 + 0.2 in your browser console?

If you have, you'll see that the answer is not 0.3 as you might expect, but instead 0.30000000000000004, this is due to inherent inaccuracy in how the IEEE 754 specification represents decimal numbers in binary (you can read more about this here).

For this reason, many languages offer some kind of decimal or precision type which trades speed and range for accuracy. These are useful for handling numbers where accuracy is more important, like financial applications.

JavaScript does not support any such type natively

 

While there are libraries available which can model decimal values more precisely, JavaScript also does not support operator overloading, which forces code to be written in method chains like:

a.add(b).dividedBy(c);

Even this simple example is not especially pretty to read, once you have a handful of these and then throw null or NaN into the mix, it starts to get pretty nasty.

 

Decimalize

This library uses Parzec in combination with BigNumber.js to deploy arithmetic expression parsing of precise decimals in the form of JS template literals

This means that instead of using method chains, you can write a simple, readable expression like

 dec`0.1 + 0.2` 

Here, the numbers will be parsed using the BigNumber.js library, rather than the JS native number type, so precision can be maintained

You can use variables as interpolated arguments in your expression

let price = dec`${cost} * ${tax}`;

You can also combine variables and static numbers in your expression

let result = dec`(${index} + 1) / ${base}`

const calculatePercentage = (amount, total) => dec`(${amount} / ${total}) * 100`

Argument Types

 

Arguments can be a number, string or BigNumber type, whatever values you pass in are immediately handed to the BigNumber constructor, and as such any invalid inputs will make the result of your expression the BigNumber representation of NaN (which can be coerced to native NaN as number type)

In future, this will be extended to allow you to configure how values such as NaN, null and undefined will be handled.

Operators

Decimalize currently supports the standard arithmetic operators, + * / - ( )

Additional operators may be added in future for exponents and other operations, but for now these are only supported by BigNumber in method syntax

Configuration

This library does not expose any configuration at the moment, however, there are various configuration options available for BigNumber.js, which you can read about over at its project page

Dependencies

The incredible BigNumber.js and the amazing Parzec, both of which are licensed under MIT, as is this library

Jasmine is also used for the test suite