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30-seconds-of-code/snippets/isArmstrongNumber.md
2017-12-27 16:26:12 +02:00

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### isArmstrongNumber
Checks if the given number is an Armstrong number or not.
Convert the given number into an array of digits. Use `Math.pow()` to get the appropriate power for each digit and sum them up. If the sum is equal to the number itself, return `true` otherwise `false`.
```js
const isArmstrongNumber = digits =>
( arr => arr.reduce( ( a, d ) => a + Math.pow( parseInt( d ), arr.length ), 0 ) == digits ? true : false )( ( digits+'' ).split( '' ) );
```
```js
isArmstrongNumber(1634) // true
isArmstrongNumber(371) // true
isArmstrongNumber(56) // false
```