A set of functions for doing financial arithmetic. This is a library you could use to build a friendlier money-math library, like the financial-number library.

1. Takes strings only
2. Does all math with the native BigInt implementation (use 1.x release if you want a version that works in older browsers)
3. Multiplication results have a precision that is twice the precision of their inputs. 9.55 * 1.50 = 14.3250
4. Addition and subtraction results have a precision as great as the highest precision of the two inputs. 1.5 + 1.00 = 2.50

Require with const math = require('financial-arithmetic-functions')

validate(str)

Can you pass it in to any of the other functions?

math.validate('123') // => true
math.validate('123.444') // => true
math.validate('123.') // => false
math.validate(123) // => false

add(a, b)

math.add('+123', '9.999') // => '132.999'
math.add('1.1', '1.234') // => '2.334'
math.add('5', '987876765654543432321') // => '987876765654543432326'

subtract(a, b)

math.subtract('123', '100') // => '23'
math.subtract('44', '-11') // => '55'
math.subtract('1.0000', '0.004') // => '0.9960'

multiply(a, b)

math.multiply('123', '0.0001') // => '0.0123'
math.multiply('99.99', '14') // => '1399.86'

getPrecision(str)

math.getPrecision('12.666') // => 3
math.getPrecision('999') // => 0

modulo(dividend, divisor)

math.modulo('10', '2') // => '0'
math.modulo('10.0', '2') // => '0.0'
math.modulo('12.33', '1') // => '0.33'
math.modulo('12.33', '1.00') // => '0.33'