happy-number
Version:
https://en.wikipedia.org/wiki/Happy_number
40 lines (21 loc) • 925 B
Markdown
A *happy number* is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number either equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process **ends in 1 are happy numbers**, while those that **do not end in 1 are unhappy numbers** (or sad numbers).
```
$ npm install --save happy-number
```
```js
const happyNumber = require('happy-number');
happyNumber(7);
//=> true
happyNumber(42);
//=> false
```
Type: `number`
MIT © [Pablo](https://github.com/ghpabs/happy-number)