Implement cardValidator with validation rules and passing tests

Author: arunkumarakilan

Sprint-3/4-stretch/card-validator.js

@@ -0,0 +1,37 @@
+function cardValidator(cardNumber)
+{
+    if(cardNumber.length !==16)
+    {
+        throw new Error("card number length must be 16");
+    }
+    let sum = 0;
+    for(let i = 0; i<15; i++)
+    {
+        if(cardNumber[i]<"0" || cardNumber[i]>"9")
+        {
+            throw new Error("not a valid number");
+        }
+       
+        sum = sum + Number(cardNumber[i]);
+    }
+    for(let i = 1; i< cardNumber.length;i++)
+    {
+         if(cardNumber[0] == cardNumber[i])
+        {
+          throw new Error(" should have at least two different digits represented");
+        }
+    }
+    if(sum <= 16)
+    {
+        throw new Error("sum of all number less than 16");
+    }
+    else if(cardNumber.slice(-1)%2 !== 0 )
+    {
+        throw new Error("last digit not an even number");
+    }
+    else
+    {
+        return true;
+    }
+}
+     module.exports = cardValidator;

Sprint-3/4-stretch/card-validator.md

@@ -1,11 +1,11 @@
 ## **PROJECT: Credit Card Validator**
 
 In this project you'll write a script that validates whether or not a credit card number is valid.
-
+ You must have at least two different digits represented (all of the digits cannot be the same).
 Here are the rules for a valid number:
 
 - Number must be 16 digits, all of them must be numbers.
-- You must have at least two different digits represented (all of the digits cannot be the same).
+-
 - The final digit must be even.
 - The sum of all the digits must be greater than 16.
 

Sprint-3/4-stretch/card-validator.test.js

@@ -0,0 +1,26 @@
+const cardValidator = require("./card-validator");
+
+test("Should card number length must be 16", ()=>{
+    const cardNumber = "546313000814253";
+    expect(()=> cardValidator(cardNumber)).toThrow();
+});
+test("should all of them must be Number", ()=>{
+    const cardNumber = "546313000814253A";
+    expect(()=> cardValidator(cardNumber)).toThrow();
+    });
+    test(" should have at least two different digits represented", ()=>{
+        const cardNumber = "1111111111111111";
+        expect(()=> cardValidator(cardNumber)).toThrow();
+    })
+test("should The sum of all the digits must be greater than 16", ()=>{
+    const cardNumber = "1111111111111111";
+    expect(()=> cardValidator(cardNumber)).toThrow();
+});
+test("should the final digit must be even", ()=>{
+    const cardNumber = "5463130008141535";
+    expect(()=> cardValidator(cardNumber)).toThrow();
+});
+test("Should a valid card Number", ()=>{
+    const cardNumber = "5463130076112436";
+    expect(cardValidator(cardNumber)).toEqual(true);
+});