Update luhnCheck

snippets/luhnCheck.md

@@ -2,23 +2,23 @@
 title: luhnCheck
 tags: math,algorithm,advanced
 firstSeen: 2018-01-03T11:02:35+02:00
-lastUpdated: 2021-10-13T19:29:39+02:00
+lastUpdated: 2022-01-30T13:37:39+02:00
 ---
 
 Implements the [Luhn Algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm) used to validate a variety of identification numbers, such as credit card numbers, IMEI numbers, National Provider Identifier numbers etc.
 
-- Use `String.prototype.split('')`, `Array.prototype.reverse()` and `Array.prototype.map()` in combination with `parseInt()` to obtain an array of digits.
-- Use `Array.prototype.splice(0, 1)` to obtain the last digit.
+- Use `String.prototype.split()`, `Array.prototype.reverse()` and `Array.prototype.map()` in combination with `parseInt()` to obtain an array of digits.
+- Use `Array.prototype.shift()` to obtain the last digit.
 - Use `Array.prototype.reduce()` to implement the Luhn Algorithm.
 - Return `true` if `sum` is divisible by `10`, `false` otherwise.
 
 ```js
 const luhnCheck = num => {
-  let arr = (num + '')
+  const arr = (num + '')
     .split('')
     .reverse()
     .map(x => parseInt(x));
-  let lastDigit = arr.splice(0, 1)[0];
+  const lastDigit = arr.shift();
   let sum = arr.reduce(
     (acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val *= 2) > 9 ? val - 9 : val)),
     0