From 7d50f43c13131e2942002b55e9c016357b1a94bf Mon Sep 17 00:00:00 2001
From: Rohit Tanwar <31792358+kriadmin@users.noreply.github.com>
Date: Wed, 3 Jan 2018 14:32:35 +0530
Subject: [PATCH] Create luhnCheck.md

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 create mode 100644 snippets/luhnCheck.md

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+### luhnCheck
+
+Implementation of 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.
+Works with numbers and strings alike
+``` js 
+const luhnCheck = num => { 
+    let arr = (num+'').split('').reverse()
+    let lastDigit = arr.splice(0,1)
+    let sum = arr.reduce((acc,val,i) => {
+	    val = parseInt(val)
+    	if(i%2!==0) return acc + val
+    	else{
+		    val = (val * 2)%9 || 9
+		    return acc+ val }
+        },0)
+     sum += parseInt(lastDigit)
+     return sum%10 === 0
+ }
+```
+```js
+ luhnCheck("4485275742308327"); //true
+ luhnCheck(4485275742308327); //true
+ luhnCheck(6011329933655299); // true
+ luhnCheck(123456789); //false
+```