isdivisiblebyx

A lightweight JavaScript library for checking if numbers are divisible by 2, 3, 4, 5, 7, or 10. Supports arbitrarily large numbers using string representation.

Features

• ✅ Check divisibility by 2, 3, 4, 5, 7, and 10
• ✅ Support for arbitrarily large numbers (beyond JavaScript's Number.MAX_SAFE_INTEGER)
• ✅ ES Module support
• ✅ TypeScript type definitions included
• ✅ Fluent API with class-based approach
• ✅ Individual function exports for tree-shaking

Installation

npm install isdivisiblebyx

Usage

Class-based API (Recommended)

import IsDiv from 'isdivisiblebyx';

const num = new IsDiv("84000");

console.log(num.by2);  // true
console.log(num.by3);  // true
console.log(num.by4);  // true
console.log(num.by5);  // true
console.log(num.by7);  // true
console.log(num.by10); // true

// Chain with set() method
const checker = new IsDiv();
console.log(checker.set("36").by2);  // true
console.log(checker.set("37").by3);  // false

Individual Functions

import {
  IsDivisibleBy2,
  IsDivisibleBy3,
  IsDivisibleBy4,
  IsDivisibleBy5,
  IsDivisibleBy7,
  IsDivisibleBy10,
} from 'isdivisiblebyx';

// Works with very large numbers as strings
console.log(IsDivisibleBy2("3626783427472374092384982309482904")); // true
console.log(IsDivisibleBy3("123456789012345678901234567890"));     // true
console.log(IsDivisibleBy5("50000000000000000"));                  // true
console.log(IsDivisibleBy7("7238723847238723849"));                // Check divisibility by 7

API Reference

IsDiv Class

Constructor

new IsDiv(num?: string | number)

Creates a new IsDiv instance with the specified number (defaults to "0").

Methods

Method	Description
set(num)	Sets a new number and returns this for chaining

Properties (Getters)

Property	Type	Description
by2	boolean	Returns true if the number is divisible by 2
by3	boolean	Returns true if the number is divisible by 3
by4	boolean	Returns true if the number is divisible by 4
by5	boolean	Returns true if the number is divisible by 5
by7	boolean	Returns true if the number is divisible by 7
by10	boolean	Returns true if the number is divisible by 10

Individual Functions

All functions accept a string representation of a number and return a boolean.

Function	Description
IsDivisibleBy2(num: string)	Checks if num is divisible by 2
IsDivisibleBy3(num: string)	Checks if num is divisible by 3
IsDivisibleBy4(num: string)	Checks if num is divisible by 4
IsDivisibleBy5(num: string)	Checks if num is divisible by 5
IsDivisibleBy7(num: string)	Checks if num is divisible by 7
IsDivisibleBy10(num: string)	Checks if num is divisible by 10

Why Use String Numbers?

JavaScript's Number type can only safely represent integers up to Number.MAX_SAFE_INTEGER (9,007,199,254,740,991). This library uses string representations to handle arbitrarily large numbers without precision loss.

// This works correctly with very large numbers!
IsDivisibleBy3("999999999999999999999999999999999999999999"); // true

Testing

npm test

Run tests with coverage:

npm run cv

License

MIT © Chadin Chaipornpisuth

Repository

GitHub