Hi, below is my solution on Github:
I made the function findInvalidCards use both of the other functions so they do not need to be called individually.
I realise compared to the solution I could have condensed the code a little. Any other feedback appreciated 
Thanks!
Ktotz
Hello guys, I have spent quite a few hours on this project and finally came up with my solution. Please kindly check it out here and let me know how I can improve/refactor my code.
I found the first function most challenging to me. When I finally completed the first function, it’s already so long! I had to separate every step clearly. Therefore, I have added some comments to clarify my thought process and hope for better readability. Thank you!
Hi everyone, I’m a bit stuck on this project, and wonder if anyone can provide a bit of assistance, I’ve tried looking through some official documentation and everything and am still a bit confused.
Around the part of creating the validateCred() function of this assignment that uses the Luhn algorithm. My first instinct for this problem is to loop over the array backwards, using the length property
for (let i = arr.length - 1; i > 0; i--)
, however the constraint of doubling every other number is a bit confusing to me
Given that only every other is changed, what happens if we revise the increment to,
i -= 2
?
This will necessitate,
let i = arr.length - 2; i -= 2
I had not thought about this, I guess if the increment is changed to - 2, it would go to every other index in the array instead.
Note also where we start, arr.length - 2 so we skip the last element of the array.
Good tips, thank you!
Here is my project without the extra challenges
Please tell me what you guys think
Thanks
Did you validate your own credit card with this? If not, then did you validate a known active credit card? Sadly, that is the only way to be absolutely sure our code works. It is, after all, a credit card validity checking program.
I guess every companies issued invalid cards
Here’s my solution to this challenge project:
I checked it against a real credit card and it correctly validated
it
Hi everyone! Hope you all are ok and improving in your code journey.
I have reached to finish this exercise some minutes ago and here is my answer. If anyone could give me some feedback it would be really appreciated
// 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];
const invalid3 = [3, 7, 5, 7, 9, 6, 0, 8, 4, 4, 5, 9, 9, 1, 4];
const invalid4 = [6, 0, 1, 1, 1, 2, 7, 9, 6, 1, 7, 7, 7, 9, 3, 5];
const invalid5 = [5, 3, 8, 2, 0, 1, 9, 7, 7, 2, 8, 8, 3, 8, 5, 4];
// Can be either valid or invalid
const mystery1 = [3, 4, 4, 8, 0, 1, 9, 6, 8, 3, 0, 5, 4, 1, 4];
const mystery2 = [5, 4, 6, 6, 1, 0, 0, 8, 6, 1, 6, 2, 0, 2, 3, 9];
const mystery3 = [6, 0, 1, 1, 3, 7, 7, 0, 2, 0, 9, 6, 2, 6, 5, 6, 2, 0, 3];
const mystery4 = [4, 9, 2, 9, 8, 7, 7, 1, 6, 9, 2, 1, 7, 0, 9, 3];
const mystery5 = [4, 9, 1, 3, 5, 4, 0, 4, 6, 3, 0, 7, 2, 5, 2, 3];
// An array of all the arrays above
const batch = [valid1, valid2, valid3, valid4, valid5, invalid1, invalid2, invalid3, invalid4, invalid5, mystery1, mystery2, mystery3, mystery4, mystery5];
// Add your functions below:
const validateCred = array => {
const finalNumber = array.reduceRight((accumulator, checkNumber, index) => {
let value = checkNumber;
//console.log('Este es el checkNumber: ' + checkNumber);
//console.log('Este es el accumulator: ' + accumulator);
//console.log(array.length - 1 - index)
if ((array.length - 1 - index) % 2 !== 0) {
value *= 2;
//console.log('Este es valor de los números impares: ' + value);
if (value > 9) {
value = value - 9;
}
}
//console.log('Esta es la suma: ' + (accumulator + value));
const newAccumulator = accumulator + value;
return newAccumulator;
});
//console.log(finalNumber)
//console.log(finalNumber % 10 === 0);
return finalNumber % 10 === 0;
};
validateCred(valid1);
const findInvalidCards = nestedArray => {
const invalidCards = nestedArray.filter(array => {
const finalNumber = array.reduceRight((accumulator, checkNumber, index) => {
let value = checkNumber;
//console.log('Este es el checkNumber: ' + checkNumber);
//console.log('Este es el accumulator: ' + accumulator);
//console.log(array.length - 1 - index)
if ((array.length - 1 - index) % 2 !== 0) {
value *= 2;
//console.log('Este es valor de los números impares: ' + value);
if (value > 9) {
value = value - 9;
}
}
//console.log('Esta es la suma: ' + (accumulator + value));
const newAccumulator = accumulator + value;
return newAccumulator;
});
//console.log(finalNumber)
//console.log(finalNumber % 10 === 0);
return finalNumber % 10 === 0;
})
//console.log(invalidCards);
return invalidCards;
};
const invalidCardsChecked = findInvalidCards(batch);
//console.log(invalidCardsChecked)
const idInvalidCardCompanies = (nestedArray) => {
const companiesWithInvalidCards = [];
const findFirstElement = nestedArray.forEach(array => {
const copiedArray = [... array];
const firstElement = copiedArray.shift();
if (firstElement === 4 && companiesWithInvalidCards.some(element => element === 'Visa') !== true) {
companiesWithInvalidCards.push('Visa');
} else if (firstElement === 3 && companiesWithInvalidCards.some(element => element === 'Amex (American Express)') !== true) {
companiesWithInvalidCards.push('Amex (American Express)');
} else if (firstElement === 5 && companiesWithInvalidCards.some(element => element === 'Mastercard') !== true) {
companiesWithInvalidCards.push('Mastercard');
} else if (firstElement === 6 && companiesWithInvalidCards.some(element => element === 'Discover') !== true) {
companiesWithInvalidCards.push('Discover');
}
});
console.log(`This are the companies with invalid credit cards: ${companiesWithInvalidCards}`)
return companiesWithInvalidCards;
};
//idInvalidCardCompanies(invalidCardsChecked);
//Convertion of a credit card number string into an array
const convertStringToArray = string => {
const stringToArray = Array.from(string).map(number => parseInt(number));
return stringToArray;
};
//convertStringToArray('456326532623232');
Cheers and keep pushing,
Sergio
I mean a win is a win