jezen/is-thirteen

Check if a number is equal to 13.

6,176

stars

458

commits

JavaScript

primary language

Jan 29, 2026

updated

README

Special thanks to @casdr for the logo

is-thirteen

Build Status

An npm package to check if a number is equal to 13.

Installation

npm --save i is-thirteen

or

yarn add is-thirteen

Usage

const isThirteen = require('is-thirteen');

// PLEAS READ THE SOURCE CODE BECAuse we moved fast and broke things

i̶s̶T̶h̶i̶r̶t̶e̶e̶n̶(̶2̶5̶)̶;̶ ̶/̶/̶ ̶f̶a̶l̶s̶e̶
i̶s̶T̶h̶i̶r̶t̶e̶e̶n̶(̶1̶3̶)̶;̶ ̶/̶/̶ ̶t̶r̶u̶e̶
const is = require('is-thirteen');
// Now with elegant syntax.

is(13).thirteen(); // true
is(12.8).roughly.thirteen(); // true
is(6).within(10).of.thirteen(); // true
is(2011).yearOfBirth(); // true

// check your math skillz
is(4).plus(5).thirteen();      // false
is(12).plus(1).thirteen();    // true
is(4).minus(12).thirteen();    // false
is(14).minus(1).thirteen();    // true
is(1).times(8).thirteen();    // false
is(26).divideby(2).thirteen();  // true

Test

npm test

License

WTFPL

A helpful tool by Jezen Thomas with helpful help from Gytis Daujotas and many fine folk.

Contributors

(top 30 of 145)

gytdau

94 commits

konkked

55 commits

Almenon

51 commits

jezen

26 commits

jezen/is-thirteen

Check if a number is equal to 13.

6,176

stars

458

commits

JavaScript

primary language

Jan 29, 2026

updated

README

Special thanks to @casdr for the logo

is-thirteen

Build Status

An npm package to check if a number is equal to 13.

Installation

npm --save i is-thirteen

or

yarn add is-thirteen

Usage

const isThirteen = require('is-thirteen');

// PLEAS READ THE SOURCE CODE BECAuse we moved fast and broke things

i̶s̶T̶h̶i̶r̶t̶e̶e̶n̶(̶2̶5̶)̶;̶ ̶/̶/̶ ̶f̶a̶l̶s̶e̶
i̶s̶T̶h̶i̶r̶t̶e̶e̶n̶(̶1̶3̶)̶;̶ ̶/̶/̶ ̶t̶r̶u̶e̶
const is = require('is-thirteen');
// Now with elegant syntax.

is(13).thirteen(); // true
is(12.8).roughly.thirteen(); // true
is(6).within(10).of.thirteen(); // true
is(2011).yearOfBirth(); // true

// check your math skillz
is(4).plus(5).thirteen();      // false
is(12).plus(1).thirteen();    // true
is(4).minus(12).thirteen();    // false
is(14).minus(1).thirteen();    // true
is(1).times(8).thirteen();    // false
is(26).divideby(2).thirteen();  // true

Test

npm test

License

WTFPL

A helpful tool by Jezen Thomas with helpful help from Gytis Daujotas and many fine folk.

Contributors

(top 30 of 145)

gytdau

94 commits

konkked

55 commits

Almenon

51 commits

jezen

26 commits

Languages

JavaScript

87.1%

Python

12.9%