@steve02081504/bigfloat

A simple JavaScript library for arbitrary-precision arithmetic, also known as "bigfloat". This implementation is inspired by elc.

It allows you to work with very large numbers and high-precision decimals without floating-point inaccuracies. It represents numbers as fractions, enabling precise calculations.

Features

- Infinite Precision: Numbers are stored as fractions (numerator and denominator) for maximum precision.
- Basic Arithmetic: Supports addition, subtraction, multiplication, division, modulus, and power operations.
- Comparisons: Accurately compare numbers.
- String Conversion: Handles conversion to and from strings, including support for repeating decimals (e.g., 0.3[3]).
- Expression Evaluation: Includes a built-in eval function to parse and compute mathematical expressions from a string.

Installation

``bash
npm install @steve02081504/bigfloat
`

Usage

$3

`javascript
import { bigfloat } from '@steve02081504/bigfloat';

const a = bigfloat('10').div(bigfloat('3')); // 10/3
const b = new bigfloat('0.5'); // 1/2

console.log(a.toString()); // '3.[3]'
console.log(b.toString()); // '0.5'

// Addition
const sum = a.add(b);
console.log(sum.toString()); // '3.8[3]' (10/3 + 1/2 = 23/6)

// Multiplication
const product = a.mul(b);
console.log(product.toString()); // '1.[6]' (10/3 * 1/2 = 10/6)

// Negative numbers
const c = new bigfloat('-123.456');
console.log(c.neg().toString()); // '123.456'
`

$3

The library can parse and represent repeating (recurring) decimals using bracket notation [].

`javascript
import { bigfloat } from '@steve02081504/bigfloat';

// Parse a repeating decimal
const repeating = bigfloat('0.[1]'); // 1/9
console.log(repeating.toString()); // '0.[1]'

const result = repeating.mul(bigfloat('9'));
console.log(result.toString()); // '1'
`

$3

Use the static bigfloat.eval() method to evaluate mathematical expressions from a string.

`javascript
import { bigfloat } from './main.mjs';

const result1 = bigfloat.eval('1.2 * (3.4 + 5.6)');
console.log(result1.toString()); // '10.8'

const result2 = bigfloat.eval('(1/3) + (2/7)');
console.log(result2.toString()); // '0.[428571]' (13/21)

const result3 = bigfloat.eval('2**100');
console.log(result3.toString()); // '1267650600228229401496703205376'
`

Supported operators in eval:
- +, -, , /, %, * (power)
- ==, !=, <, >, <=, >=
- &&, ||, ! (logical)
- Parentheses () for grouping.

API

$3


Creates a new bigfloat instance. value can be a string, number, or another bigfloat instance.

$3

- .add(other)
- .sub(other)
- .mul(other)
- .div(other)
- .mod(other)
- .pow(other)

$3

- .equals(other)
- .lessThan(other)
- .greaterThan(other)
- .compare(other): Returns 1 if greater, -1 if less, 0 if equal.

$3

- .neg(): Returns the negated value.
- .abs(): Returns the absolute value.
- .floor(): Returns the floor of the number.
- .toString(): Converts the number to its string representation, using [] for repeating decimals.

$3

- bigfloat.eval(expression): Evaluates a mathematical expression string.
- bigfloat.fromString(string): Creates a bigfloat` from a string.