Credit Card Checker Challenge Project (JavaScript)

digital5742616870 · August 20, 2023, 7:54am

This is one small step for a programmer’s career, one giant step towards motivation.
Obviously not the most elegant solution, but it works

gist.github.com

https://gist.github.com/codecademydev/b67d3825dcf8501f12a2483472fa8d8c

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];

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dguy96 · August 23, 2023, 1:49am

I need a total video walkthrough of this project because Im not understanding this one point. The moment I think I’ve solved an issue I’m immediately met with one after the other - and I’m not understanding the process and why things work they way they do. D:

ciarangold · August 23, 2023, 2:35pm

Hi,
I think validateCred is mutating the arrays you pass through it due to const ccnum = arr

Inside the loop, (ccnum[i] *= 2) mutates. The original array arr is modified directly.
This happens again at ccnum[i] -= 9

w3b_master · August 23, 2023, 3:08pm

Hi All,
Just finished the Challenge Project: Credit Card Checker. I was a really good challenge and valuable learning.
Definitely not the most effective solution, any advice is appreciated.

gist.github.com

https://gist.github.com/w3bscout/b623cde60c4c97571fb25099b350ea09

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];

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mikedinis · August 23, 2023, 4:44pm

Hello!
Instead of
const ccnum = arr;
Use this
const ccnum = arr.slice(0);
Cheers!

marcelaobeso · August 24, 2023, 8:38pm

My solution :3 any suggestions on how to improve it will we highly appreciated

gist.github.com

https://gist.github.com/codecademydev/8a607c4c0358b9eeca25cf0169c84fd6

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8]
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9]
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6]
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5]
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6]

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5]
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3]

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nabi-cloud · August 25, 2023, 4:09pm

And here I thought I could escape math!

But this was an enjoyable problem-solving, indeed. Whenever I start to work on this project, hours seem to pass so fast. I also find it challenging to break off on this for a while because I can’t stop thinking of how to solve this project haha

I did the project extension, wherein I could input a number and use the same function from the original requirements of the project. I also added the credit card number generator (this one was challenging), which generates a valid card number.

Feel free to check on how I did it here.

brianfugate · August 26, 2023, 11:25pm

Ok, here is my solution to this project:

https://github.com/BrianFugate/codecademy-credit-card-checker/blob/f1484b93c91fc6cb9f2aed93f6abe7b816c7b15e/main.js

Any feedback, good or bad, would be much appreciated! I really enjoyed completing this project and I look forward to browsing other people’s solutions as well.

lamphrangmi · August 27, 2023, 3:20pm

Here’s my solution:
https://gist.github.com/codecademydev/b364871fe81ed90ea25569ad519ef210

brianfugate · August 27, 2023, 7:46pm

marcelaobeso,

When I first saw your code for the card digit sum calculator my head spun and I thought there was no way that works. I am not very good with using the ternary operators and I did not follow your logic. However, once I copied it, studied how it worked, and ran it in Node.js I am very impressed. I definately need to practice using ternary operators after seeing your work. Thanks!
Brian

brianfugate · August 27, 2023, 8:02pm

lamphrangmi,

I’m sorry to be the bearer of bad news, but your code does not work. This portion of your validateCred function is missing some logic:

for (let i = arr.length -1; i >=0; i–) {
if (i % 2 == 0) {
arr[i] = arr[i] * 2;
if (arr[i] > 9) {
arr[i] = arr[i] - 9;
}
}
}

If you are going to count your loop down from length-1 then you have to account for whether or not there are an even or odd number of digits in the card number. If you do not account for this then you will be doubling the wrong digit sometimes. Here is some code I made to verify the functions work properly. Feel free to paste it at the end of your code to check things out.

// calling functions for testing

// test all cards in batch array
console.log(‘\n\nTesting all cards in batch array’)
for (const card of batch) {
if (validateCred(card) == true) {
console.log(card.join(‘’) + ’ is valid’);
} else {
console.log(card.join(‘’) + ’ is invalid’);
}
}

// display all invalid card nums
console.log(‘\n\nThese card numbers are invalid’)
for (const card of findInvalidCards(batch)) {
console.log(card.join(‘’));
}

// display card companies who issued bad cards
console.log(“\n\nThese credit card companies issued bad card numbers:”)
console.log(idInvalidCardCompanies(findInvalidCards(batch)).join(', '));

This is what the output of that code should be:

$ node main.js

Testing all cards in batch array
4539677908016808 is valid
5535766768751439 is valid
371612019985236 is valid
6011144340682905 is valid
4539404967869666 is valid
4532778771091795 is invalid
5795593392134643 is invalid
375796084459914 is invalid
6011127961777935 is invalid
5382019772883854 is invalid
344801968305414 is invalid
5466100861620239 is valid
6011377020962656203 is invalid
4929877169217093 is invalid
4913540463072523 is valid

These card numbers are invalid
4532778771091795
5795593392134643
375796084459914
6011127961777935
5382019772883854
344801968305414
6011377020962656203
4929877169217093

These credit card companies issued bad card numbers:
Visa, Mastercard, Amex (American Express), Discover

mikedinis · August 29, 2023, 6:37pm

Hello!
Thank you very much for posting!
Loved the way you chained the ternary operator and how you used the new Set =)
Just one thing, the function validateCred(array) seems to only work properly for even length cards?
Cheers!

giga0871510499 · August 29, 2023, 10:35pm

Thanks, I’ll fix that

data0328193865 · September 1, 2023, 4:04pm

Hi, this is my solution : GitHub - Sonfresh/Challenge-Project-Credit-Card-Checker at 6fc1227e41741e51d7503efda6cf9f2f20083c6f

arodzuri · September 2, 2023, 1:42am

Hola con todos, esta es mi solución al Verificador de Tarjetas, espero les ayude

gist.github.com

https://gist.github.com/codecademydev/8de8744a7432b5fcfa7c754dfa84f62c

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];

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hector_cryo · September 11, 2023, 3:36pm

I’ve enjoyed this challenge!
Feel free to take a look at how I implemented the main (and optional) tasks here:

gist.github.com

https://gist.github.com/codecademydev/99214e9570dd49e9d2bb0979245b6eeb

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];
const valid6 = [4, 5, 3, 2, 3, 3, 8, 7, 0, 5, 8, 2, 1, 0, 1, 8]

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];

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unstoppableforce · September 13, 2023, 10:26pm

gist.github.com

https://gist.github.com/codecademydev/b0ee380a8a246c45a27f39ce88ddb79c

main.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];

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here is my solution guys any feedback is welcome

byvcraft · September 14, 2023, 2:48pm

Hi all!
here is my solution for this challenge. I did the opening task also.
Feel free to comment. thank you!

github.com

Quanbui86/quanbui86.github.io/blob/main/helloJavaScript/credit-card-checker-starter/main.js#L47


      
                          }                
                  }         
                  for (j=len-2; j>=0; j-=2){
                          temp2 = temp2 + card[j]
                  }
                  if ((temp1a + temp1b + temp2)%10 === 0){
                          return 10
                  }else return (temp1a + temp1b + temp2)%10
          }
          
          function validateCred(card) {        
                  if((checkNumber(card) + card[len])%10 === 0) {
                          return true
                  }       return false                   
          }
          function checkCards (cards) {
                  for (card of cards) {
                          if (validateCred(card)) {
                                  console.log(`No${cards.indexOf(card) + 1}: ${card} is valid`)
                          } else console.log(`No${cards.indexOf(card) + 1}: ${card} is invalid - check again`)
                  }

seansim1806 · September 19, 2023, 8:00am

gist.github.com

https://gist.github.com/sena0112/cb16db109177fb00588019518eb14362

Credit-Card-Checker.js

// All valid credit card numbers
const valid1 = [4, 5, 3, 9, 6, 7, 7, 9, 0, 8, 0, 1, 6, 8, 0, 8];
const valid2 = [5, 5, 3, 5, 7, 6, 6, 7, 6, 8, 7, 5, 1, 4, 3, 9];
const valid3 = [3, 7, 1, 6, 1, 2, 0, 1, 9, 9, 8, 5, 2, 3, 6];
const valid4 = [6, 0, 1, 1, 1, 4, 4, 3, 4, 0, 6, 8, 2, 9, 0, 5];
const valid5 = [4, 5, 3, 9, 4, 0, 4, 9, 6, 7, 8, 6, 9, 6, 6, 6];

// All invalid credit card numbers
const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];

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Done. Do feedback if there’s anything I can improve on! Thanks!

arc0385292563 · September 19, 2023, 6:59pm

Hello,

Here is my solution :

Thank you for your feedbacks !
Pierre