Introduction
decimal is a small and concise library that provides Decimal type for clojurescript.
Warning

This documentation does not covers all api, so if you miss some function, contributions are very welcome. You can see the full API documentation here. 
Project Maturity
Since decimal is a young project there can be some API breakage.
Install
The simplest way to use decimal in a clojurescript project, is by including it in the dependency vector on your project.clj file:
[funcool/decimal "1.0.2"]
Use
To start using it you have to require the decimal.core
namespace.
(require '[decimal.core :as dc])
It accepts a value of type number, string or Decimal.
(let [x (dc/decimal 123.4567)
y (dc/decimal "123456.7e3")
z (dc/decimal x)]
(dc/= x y z))
A value can also be in binary, hexadecimal or octal if the appropriate prefix is included.
(let [x (dc/decimal "0xff.f")
y (dc/decimal "0b10101100")
z (dc/+ x y)]
(dc/tobinary z) ;; "0b110101011.1111"
(dc/tobinary z 13)) ;; "0b1.101010111111p+8"
The methods that return a Decimal can be chained.
(> (dc/decimal 11)
(dc/div 2)
(dc/mul 9)
(dc/floor)) ;; #decimal 49
Almost all of the methods of JavaScript’s Math object are also replicated.
(dc/sqrt "6.98372465832e+9823") ;; #decimal 8.3568682281821340204e+4911
(dc/pow 2 0.0979843) ;; #decimal 1.0702770511687781839
There are NaN?
and finite?
methods, as NaN
and Infinity
are valid Decimal
values,
(dc/NaN? (dc/decimal js/NaN)) ;; true
(dc/finite? (dc/decimal js/Infinity)) ;; false
and a tofraction
method with an optional maximum denominator argument
(let [pi (dc/div (dc/decimal 355) 113)]
(dc/tofraction pi) ;; [#decimal 31415929203539823009 #decimal 10000000000000000000]
(dc/tofraction pi 1000)) ;; [#decimal 355 #decimal 113]
All calculations are rounded according to the number of significant digits and rounding mode specified by the precision and rounding properties of the Decimal constructor.
Multiple Decimal constructors can be created, each with their own independent configuration which applies to all Decimal numbers created from it.
;; Set the precision and rounding of the default Decimal constructor
(dc/config! {:precision 5 :rounding :roundhalfup})
;; Create another Decimal constructor, optionally passing in a configuration object
(let [decimal10 (dc/config {:precision 10 :rounding :rounddown})
x (dc/decimal 5)
y (decimal10 5)]
(dc/div x 3) ;; #decimal 1.6667
(dc/div y 3)) ;; #decimal 1.666666666
Developers Guide
Philosophy
Five most important rules:

Beautiful is better than ugly.

Explicit is better than implicit.

Simple is better than complex.

Complex is better than complicated.

Readability counts.
All contributions to decimal should keep these important rules in mind.
Contributing
Unlike Clojure and other Clojure contributed libraries decimal does not have many restrictions for contributions. Just open an issue or pull request.
Source Code
decimal is open source and can be found on github.
You can clone the public repository with this command:
git clone https://github.com/funcool/decimal
License
decimal is licensed under BSD (2Clause) license:
Copyright (c) 20152017 Andrey Antukh <niwi@niwi.nz> Copyright (c) 20172017 JesÃºs Espino <jespinog@gmail.com> All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.