12 lines
323 B
JavaScript
12 lines
323 B
JavaScript
const luhnCheck = num => {
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let arr = (num + '')
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.split('')
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.reverse()
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.map(x => parseInt(x));
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let lastDigit = arr.splice(0, 1)[0];
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let sum = arr.reduce((acc, val, i) => (i % 2 !== 0 ? acc + val : acc + ((val * 2) % 9) || 9), 0);
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sum += lastDigit;
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return sum % 10 === 0;
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};
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module.exports = luhnCheck;
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