38 lines
806 B
Plaintext
38 lines
806 B
Plaintext
import assertString from './util/assertString';
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var isin = /^[A-Z]{2}[0-9A-Z]{9}[0-9]$/;
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export default function isISIN(str) {
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assertString(str);
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if (!isin.test(str)) {
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return false;
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}
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var checksumStr = str.replace(/[A-Z]/g, function (character) {
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return parseInt(character, 36);
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});
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var sum = 0;
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var digit;
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var tmpNum;
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var shouldDouble = true;
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for (var i = checksumStr.length - 2; i >= 0; i--) {
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digit = checksumStr.substring(i, i + 1);
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tmpNum = parseInt(digit, 10);
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if (shouldDouble) {
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tmpNum *= 2;
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if (tmpNum >= 10) {
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sum += tmpNum + 1;
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} else {
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sum += tmpNum;
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}
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} else {
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sum += tmpNum;
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}
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shouldDouble = !shouldDouble;
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}
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return parseInt(str.substr(str.length - 1), 10) === (10000 - sum) % 10;
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} |