51 lines
1.1 KiB
JavaScript
51 lines
1.1 KiB
JavaScript
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import assertString from './util/assertString';
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var isbn10Maybe = /^(?:[0-9]{9}X|[0-9]{10})$/;
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var isbn13Maybe = /^(?:[0-9]{13})$/;
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var factor = [1, 3];
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export default function isISBN(str) {
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var version = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : '';
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assertString(str);
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version = String(version);
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if (!version) {
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return isISBN(str, 10) || isISBN(str, 13);
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}
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var sanitized = str.replace(/[\s-]+/g, '');
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var checksum = 0;
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var i;
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if (version === '10') {
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if (!isbn10Maybe.test(sanitized)) {
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return false;
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}
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for (i = 0; i < 9; i++) {
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checksum += (i + 1) * sanitized.charAt(i);
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}
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if (sanitized.charAt(9) === 'X') {
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checksum += 10 * 10;
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} else {
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checksum += 10 * sanitized.charAt(9);
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}
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if (checksum % 11 === 0) {
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return !!sanitized;
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}
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} else if (version === '13') {
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if (!isbn13Maybe.test(sanitized)) {
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return false;
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}
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for (i = 0; i < 12; i++) {
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checksum += factor[i % 2] * sanitized.charAt(i);
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}
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if (sanitized.charAt(12) - (10 - checksum % 10) % 10 === 0) {
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return !!sanitized;
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}
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}
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return false;
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}
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