gistfile1.txt

Credit Card Validator

Using the Luhn Algorithm, also known as "modulus 10", we will be determining the validity of a given credit card number.

For now, we are just editing the included .js file. You will find the skeleton of the CreditCard prototype inside.

The Class

We want our class to have its three main properties set on instantiation - ccNum, cardType, and valid. If the card number given passes the Luhn algorithm, valid should be true and cardType should be set to 'VISA', 'AMEX', etc. If it does not pass, valid should be false and cardType should be set to "INVALID"

This way, we can do this:

    myCard = new CreditCard('347650202246884')

    myCard.valid // true
    myCard.cardType // 'AMEX'
    myCard.ccNum // '347650202246884'
There are three prototype functions.

CreditCard.prototype.validStartingNums should check whether or not the credit card has valid starting numbers.

Visa must start with 4
Mastercard must start with 51, 52, 53, 54 or 55
AMEX must start with 34 or 37
Discover must start with 6011

CreditCard.prototype.checkLength should check whether or not a credit card number is a valid length.

Visa, MC and Discover have 16 digits
AMEX have 15

CreditCard.prototype.validate should run the Luhn Algorithm and return true or false.

The Algorithm

From the right most digit, double the value of every second digit. For example:

4 4 8 5 0 4 0 9 9 3 2 8 7 6 1 6

becomes

8 4 16 5 0 4 0 9 18 3 4 8 14 6 2 6

Now, sum all the individual digits together. That is to say, split any numbers with two digits into their individual digits and add them. Like so:

8 + 4 + 1 + 6 + 5 + 0 + 4 + 0 + 9 + 1 + 8 + 3 + 4 + 8 + 1 + 4 + 6 + 2 + 6

Now take the sum of those numbers and modulo 10.

80 % 10

If the result is 0, the credit card number is valid.

Tests

Make sure your code passes all the assert tests.

Write your own assert tests to test any other possible cases where your code might fail.

Goals

Keep your code super clean and DRY.

If you are repeating yourself, stop and think about how to better approach the problem.

Keep your code encapsulated - imagine your CreditCard class is an interface other code will need to read. You want it as separate and unentangled as possible. Your class should not be dependent on any code outside of it - except, of course, code to instantiate it.Credit Card Validator

Using the Luhn Algorithm, also known as "modulus 10", we will be determining the validity of a given credit card number.

For now, we are just editing the included .js file. You will find the skeleton of the CreditCard prototype inside.

The Class

We want our class to have its three main properties set on instantiation - ccNum, cardType, and valid. If the card number given passes the Luhn algorithm, valid should be true and cardType should be set to 'VISA', 'AMEX', etc. If it does not pass, valid should be false and cardType should be set to "INVALID"

This way, we can do this:

    myCard = new CreditCard('347650202246884')

    myCard.valid // true
    myCard.cardType // 'AMEX'
    myCard.ccNum // '347650202246884'
There are three prototype functions.

CreditCard.prototype.validStartingNums should check whether or not the credit card has valid starting numbers.

Visa must start with 4
Mastercard must start with 51, 52, 53, 54 or 55
AMEX must start with 34 or 37
Discover must start with 6011

CreditCard.prototype.checkLength should check whether or not a credit card number is a valid length.

Visa, MC and Discover have 16 digits
AMEX have 15

CreditCard.prototype.validate should run the Luhn Algorithm and return true or false.

The Algorithm

From the right most digit, double the value of every second digit. For example:

4 4 8 5 0 4 0 9 9 3 2 8 7 6 1 6

becomes

8 4 16 5 0 4 0 9 18 3 4 8 14 6 2 6

Now, sum all the individual digits together. That is to say, split any numbers with two digits into their individual digits and add them. Like so:

8 + 4 + 1 + 6 + 5 + 0 + 4 + 0 + 9 + 1 + 8 + 3 + 4 + 8 + 1 + 4 + 6 + 2 + 6

Now take the sum of those numbers and modulo 10.

80 % 10

If the result is 0, the credit card number is valid.

Tests

Make sure your code passes all the assert tests.

Write your own assert tests to test any other possible cases where your code might fail.

Goals

Keep your code super clean and DRY.

If you are repeating yourself, stop and think about how to better approach the problem.

Keep your code encapsulated - imagine your CreditCard class is an interface other code will need to read. You want it as separate and unentangled as possible. Your class should not be dependent on any code outside of it - except, of course, code to instantiate it.