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reformat LuhnAlgorithm.js and LuhnAlgorithm.test.js using Prettier
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HD-40307g committed Dec 20, 2024
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136 changes: 77 additions & 59 deletions Maths/LuhnAlgorithm.js
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@@ -1,96 +1,114 @@
/**
* Luhn algorithm, also known as the “Modulus 10” or “mod 10” algorithm.
* Luhn algorithm, also known as the “Modulus 10” or “mod 10” algorithm.
* This algorithm is a simple checksum formula used to validate the authenticity of credit card numbers.
* The Luhn algorithm works by doubling every second digit from right to left, adding the resulting digits, and then checking if the total is divisible by 10.
* The Luhn algorithm works by doubling every second digit from right to left, adding the resulting digits, and then checking if the total is divisible by 10.
* If it is, the credit card number is considered valid.
* The Luhn algorithm is widely used in credit card verification and is specified in ISO/IEC 7812-1.
* The Luhn algorithm is widely used in credit card verification and is specified in ISO/IEC 7812-1.
* It is not intended to be a cryptographically secure hash function but rather a simple method to detect accidental errors, not malicious attacks.
* https://en.wikipedia.org/wiki/Luhn_algorithm
*/

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

// Invalid credit card numbers
export const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5];
export const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3];
export const invalid3 = [3, 7, 5, 7, 9, 6, 0, 8, 4, 4, 5, 9, 9, 1, 4];
export const invalid4 = [6, 0, 1, 1, 1, 2, 7, 9, 6, 1, 7, 7, 7, 9, 3, 5];
export const invalid5 = [5, 3, 8, 2, 0, 1, 9, 7, 7, 2, 8, 8, 3, 8, 5, 4];
export const invalid1 = [4, 5, 3, 2, 7, 7, 8, 7, 7, 1, 0, 9, 1, 7, 9, 5]
export const invalid2 = [5, 7, 9, 5, 5, 9, 3, 3, 9, 2, 1, 3, 4, 6, 4, 3]
export const invalid3 = [3, 7, 5, 7, 9, 6, 0, 8, 4, 4, 5, 9, 9, 1, 4]
export const invalid4 = [6, 0, 1, 1, 1, 2, 7, 9, 6, 1, 7, 7, 7, 9, 3, 5]
export const invalid5 = [5, 3, 8, 2, 0, 1, 9, 7, 7, 2, 8, 8, 3, 8, 5, 4]

// Mixed batch of credit card numbers
export const mystery1 = [3, 4, 4, 8, 0, 1, 9, 6, 8, 3, 0, 5, 4, 1, 4];
export const mystery2 = [5, 4, 6, 6, 1, 0, 0, 8, 6, 1, 6, 2, 0, 2, 3, 9];
export const mystery3 = [6, 0, 1, 1, 3, 7, 7, 0, 2, 0, 9, 6, 2, 6, 5, 6, 2, 0, 3];
export const mystery4 = [4, 9, 2, 9, 8, 7, 7, 1, 6, 9, 2, 1, 7, 0, 9, 3];
export const mystery5 = [4, 9, 1, 3, 5, 4, 0, 4, 6, 3, 0, 7, 2, 5, 2, 3];
export const mystery1 = [3, 4, 4, 8, 0, 1, 9, 6, 8, 3, 0, 5, 4, 1, 4]
export const mystery2 = [5, 4, 6, 6, 1, 0, 0, 8, 6, 1, 6, 2, 0, 2, 3, 9]
export const mystery3 = [
6, 0, 1, 1, 3, 7, 7, 0, 2, 0, 9, 6, 2, 6, 5, 6, 2, 0, 3
]
export const mystery4 = [4, 9, 2, 9, 8, 7, 7, 1, 6, 9, 2, 1, 7, 0, 9, 3]
export const mystery5 = [4, 9, 1, 3, 5, 4, 0, 4, 6, 3, 0, 7, 2, 5, 2, 3]

export const batch = [valid1, valid2, valid3, valid4, valid5, invalid1, invalid2, invalid3, invalid4, invalid5, mystery1, mystery2, mystery3, mystery4, mystery5];
export const batch = [
valid1,
valid2,
valid3,
valid4,
valid5,
invalid1,
invalid2,
invalid3,
invalid4,
invalid5,
mystery1,
mystery2,
mystery3,
mystery4,
mystery5
]

/**
* Validates a credit card number using the Luhn Algorithm.
* @param {number[]} numArr - Array representing the credit card number.
* @returns {boolean} - True if the card is valid, false otherwise.
*/
export function validateCred(numArr) {
let total = 0;
for (let i = numArr.length - 1; i >= 0; i--) {
let currValue = numArr[i];
// Double every other digit starting from the second-to-last
if ((numArr.length - 1 - i) % 2 === 1) {
currValue *= 2;
if (currValue > 9) {
currValue -= 9;
}
let total = 0
for (let i = numArr.length - 1; i >= 0; i--) {
let currValue = numArr[i]
// Double every other digit starting from the second-to-last
if ((numArr.length - 1 - i) % 2 === 1) {
currValue *= 2
if (currValue > 9) {
currValue -= 9
}
}
total += currValue;
}
return total % 10 === 0;
};
total += currValue
}
return total % 10 === 0
}

/**
* Finds invalid credit card numbers from a batch.
* @param {number[][]} cards - Array of credit card numbers.
* @returns {number[][]} - Array of invalid credit card numbers.
*/
export function findInvalidCards(cards) {
return cards.filter(card => !validateCred(card));
};
return cards.filter((card) => !validateCred(card))
}

/**
* Identifies credit card companies that issued invalid card numbers.
* @param {number[][]} invalidBatch - Array of invalid credit card numbers.
* @returns {string[]} - Array of company names.
*/
export function idInvalidCardCompanies(invalidBatch) {
const companies = new Set();
invalidBatch.forEach(card => {
switch (card[0]) {
case 3:
companies.add('Amex');
break;
case 4:
companies.add('Visa');
break;
case 5:
companies.add('Mastercard');
break;
case 6:
companies.add('Discover');
break;
default:
console.warn('Company not found for card starting with:', card[0]);
}
});
return Array.from(companies);
};
const companies = new Set()
invalidBatch.forEach((card) => {
switch (card[0]) {
case 3:
companies.add('Amex')
break
case 4:
companies.add('Visa')
break
case 5:
companies.add('Mastercard')
break
case 6:
companies.add('Discover')
break
default:
console.warn('Company not found for card starting with:', card[0])
}
})
return Array.from(companies)
}

// Example Usage
console.log(validateCred(valid1)); // Should print true
console.log(validateCred(invalid1)); // Should print false
console.log(findInvalidCards(batch)); // Find all invalid cards
console.log(idInvalidCardCompanies(findInvalidCards(batch))); // Find companies of invalid cards
console.log(validateCred(valid1)) // Should print true
console.log(validateCred(invalid1)) // Should print false
console.log(findInvalidCards(batch)) // Find all invalid cards
console.log(idInvalidCardCompanies(findInvalidCards(batch))) // Find companies of invalid cards
134 changes: 76 additions & 58 deletions Maths/test/LuhnAlgorithm.test.js
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// Import the functions to be tested
import { validateCred, findInvalidCards, idInvalidCardCompanies } from '../LuhnAlgorithm.js';
import {
validateCred,
findInvalidCards,
idInvalidCardCompanies
} from '../LuhnAlgorithm.js'
// Import credit card numbers to be tested
import { valid1, valid2, valid3, valid4, valid5, invalid1, invalid2, invalid3, invalid4, invalid5, batch } from '../LuhnAlgorithm.js';
import {
valid1,
valid2,
valid3,
valid4,
valid5,
invalid1,
invalid2,
invalid3,
invalid4,
invalid5,
batch
} from '../LuhnAlgorithm.js'

describe('Luhn Algorithm Tests', () => {
// Test for validateCred function
describe('validateCred', () => {
test('should return true for valid credit cards', () => {
const validCards = [valid1, valid2, valid3, valid4, valid5];
validCards.forEach(card => {
expect(validateCred(card)).toBe(true);
});
});

test('should return false for invalid credit cards', () => {
const invalidCards = [invalid1, invalid2, invalid3, invalid4, invalid5];
invalidCards.forEach(card => {
expect(validateCred(card)).toBe(false);
});
});
});

// Test for findInvalidCards function
describe('findInvalidCards', () => {
test('should return only invalid credit cards from a batch', () => {
const invalidCards = findInvalidCards(batch);
const allInvalid = invalidCards.every(card => !validateCred(card));
expect(allInvalid).toBe(true);
});

test('should return an empty array if no invalid cards are found', () => {
const validCards = [valid1, valid2, valid3, valid4, valid5];
const invalidCards = findInvalidCards(validCards);
expect(invalidCards).toEqual([]);
});
});

// Test for idInvalidCardCompanies function
describe('idInvalidCardCompanies', () => {
test('should identify all companies that issued invalid cards', () => {
const invalidCards = findInvalidCards(batch);
const companies = idInvalidCardCompanies(invalidCards);

// Expect the companies array to include known companies
expect(companies).toEqual(expect.arrayContaining(['Visa', 'Mastercard', 'Amex', 'Discover']));
});

test('should return an empty array if no invalid cards are found', () => {
const validCards = [valid1, valid2, valid3, valid4, valid5];
const invalidCards = findInvalidCards(validCards); // Ensure only invalid cards are processed
const companies = idInvalidCardCompanies(invalidCards);
expect(companies).toEqual([]);
});

test('should handle unknown card companies gracefully', () => {
const unknownCard = [9, 3, 1, 8, 2, 0, 7, 4, 5, 6, 7, 8, 9];
const companies = idInvalidCardCompanies([unknownCard]);
expect(companies).not.toContain('Unknown');
});
});
});
// Test for validateCred function
describe('validateCred', () => {
test('should return true for valid credit cards', () => {
const validCards = [valid1, valid2, valid3, valid4, valid5]
validCards.forEach((card) => {
expect(validateCred(card)).toBe(true)
})
})

test('should return false for invalid credit cards', () => {
const invalidCards = [invalid1, invalid2, invalid3, invalid4, invalid5]
invalidCards.forEach((card) => {
expect(validateCred(card)).toBe(false)
})
})
})

// Test for findInvalidCards function
describe('findInvalidCards', () => {
test('should return only invalid credit cards from a batch', () => {
const invalidCards = findInvalidCards(batch)
const allInvalid = invalidCards.every((card) => !validateCred(card))
expect(allInvalid).toBe(true)
})

test('should return an empty array if no invalid cards are found', () => {
const validCards = [valid1, valid2, valid3, valid4, valid5]
const invalidCards = findInvalidCards(validCards)
expect(invalidCards).toEqual([])
})
})

// Test for idInvalidCardCompanies function
describe('idInvalidCardCompanies', () => {
test('should identify all companies that issued invalid cards', () => {
const invalidCards = findInvalidCards(batch)
const companies = idInvalidCardCompanies(invalidCards)

// Expect the companies array to include known companies
expect(companies).toEqual(
expect.arrayContaining(['Visa', 'Mastercard', 'Amex', 'Discover'])
)
})

test('should return an empty array if no invalid cards are found', () => {
const validCards = [valid1, valid2, valid3, valid4, valid5]
const invalidCards = findInvalidCards(validCards) // Ensure only invalid cards are processed
const companies = idInvalidCardCompanies(invalidCards)
expect(companies).toEqual([])
})

test('should handle unknown card companies gracefully', () => {
const unknownCard = [9, 3, 1, 8, 2, 0, 7, 4, 5, 6, 7, 8, 9]
const companies = idInvalidCardCompanies([unknownCard])
expect(companies).not.toContain('Unknown')
})
})
})

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