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73 lines
1.8 KiB
73 lines
1.8 KiB
"use strict"; |
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Object.defineProperty(exports, "__esModule", { |
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value: true |
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}); |
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exports.default = isISIN; |
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var _assertString = _interopRequireDefault(require("./util/assertString")); |
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } |
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var isin = /^[A-Z]{2}[0-9A-Z]{9}[0-9]$/; // this link details how the check digit is calculated: |
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// https://www.isin.org/isin-format/. it is a little bit |
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// odd in that it works with digits, not numbers. in order |
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// to make only one pass through the ISIN characters, the |
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// each alpha character is handled as 2 characters within |
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// the loop. |
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function isISIN(str) { |
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(0, _assertString.default)(str); |
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if (!isin.test(str)) { |
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return false; |
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} |
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var double = true; |
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var sum = 0; // convert values |
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for (var i = str.length - 2; i >= 0; i--) { |
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if (str[i] >= 'A' && str[i] <= 'Z') { |
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var value = str[i].charCodeAt(0) - 55; |
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var lo = value % 10; |
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var hi = Math.trunc(value / 10); // letters have two digits, so handle the low order |
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// and high order digits separately. |
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for (var _i = 0, _arr = [lo, hi]; _i < _arr.length; _i++) { |
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var digit = _arr[_i]; |
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if (double) { |
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if (digit >= 5) { |
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sum += 1 + (digit - 5) * 2; |
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} else { |
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sum += digit * 2; |
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} |
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} else { |
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sum += digit; |
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} |
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double = !double; |
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} |
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} else { |
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var _digit = str[i].charCodeAt(0) - '0'.charCodeAt(0); |
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if (double) { |
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if (_digit >= 5) { |
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sum += 1 + (_digit - 5) * 2; |
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} else { |
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sum += _digit * 2; |
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} |
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} else { |
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sum += _digit; |
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} |
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double = !double; |
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} |
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} |
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var check = Math.trunc((sum + 9) / 10) * 10 - sum; |
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return +str[str.length - 1] === check; |
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} |
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module.exports = exports.default; |
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module.exports.default = exports.default; |