axelstudios/lodash-arithmetic

Lodash mixins for arbitrary-precision arithmetic

lodash-arithmetic

Lodash mixins for arbitrary-precision arithmetic

Why Lo-Dash mixins for arithmetic?

Because of binary floating-point, arithmetic operations in JavaScript may imply rounding issues like:

0.1 + 0.2 = 0.30000000000000004

You will find a complete explanation about floating-point arithmetic at http://floating-point-gui.de/.

Lodash-arithmetic provides simple Lo-Dash mixins for basic arithmetic operations: addition, subtraction, multiplication and division. Even if Lo-Dash 4 natively has the methods _.add, _.subtract, _.multiply and _.divide, they do not take in account arbitrary-precision decimal.

Let's see the following examples:

// Without Lo-Dash
console.log(0.1 + 0.2 === 0.3) // false

// With Lo-Dash 4 but without the arithmetic mixins
console.log(_.add(0.1, 0.2) === 0.3) // false

// With Lo-Dash and the arithmetic mixins
console.log(_.add(0.1, 0.2) === 0.3) // true

Install

The easiest way is to install lodash-arithmetic as dependency:

npm install lodash-arithmetic --save

Usage

Addition

_.add(0.1, 0.2); // 0.3

Subtraction

_.subtract(0.1235, 0.1234); // 0.0001

Multiplication

_.multiply(0.07, 100); // 7

Division

_.divide(8.2, 1000); // 0.0082

Chaining

_(0.1)
  .add(0.2)
  .multiply(77.1)
  .subtract(0.12345)
  .value(); // 23.00655

License

Code licensed under MIT License.