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58 lines
2.1 KiB
58 lines
2.1 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 = differenceInYears; |
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var _index = _interopRequireDefault(require("../toDate/index.js")); |
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var _index2 = _interopRequireDefault(require("../differenceInCalendarYears/index.js")); |
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var _index3 = _interopRequireDefault(require("../compareAsc/index.js")); |
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var _index4 = _interopRequireDefault(require("../_lib/requiredArgs/index.js")); |
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function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; } |
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/** |
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* @name differenceInYears |
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* @category Year Helpers |
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* @summary Get the number of full years between the given dates. |
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* |
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* @description |
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* Get the number of full years between the given dates. |
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* |
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* ### v2.0.0 breaking changes: |
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* |
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* - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes). |
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* |
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* @param {Date|Number} dateLeft - the later date |
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* @param {Date|Number} dateRight - the earlier date |
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* @returns {Number} the number of full years |
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* @throws {TypeError} 2 arguments required |
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* |
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* @example |
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* // How many full years are between 31 December 2013 and 11 February 2015? |
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* var result = differenceInYears(new Date(2015, 1, 11), new Date(2013, 11, 31)) |
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* //=> 1 |
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*/ |
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function differenceInYears(dirtyDateLeft, dirtyDateRight) { |
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(0, _index4.default)(2, arguments); |
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var dateLeft = (0, _index.default)(dirtyDateLeft); |
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var dateRight = (0, _index.default)(dirtyDateRight); |
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var sign = (0, _index3.default)(dateLeft, dateRight); |
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var difference = Math.abs((0, _index2.default)(dateLeft, dateRight)); // Set both dates to a valid leap year for accurate comparison when dealing |
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// with leap days |
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dateLeft.setFullYear('1584'); |
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dateRight.setFullYear('1584'); // Math.abs(diff in full years - diff in calendar years) === 1 if last calendar year is not full |
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// If so, result must be decreased by 1 in absolute value |
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var isLastYearNotFull = (0, _index3.default)(dateLeft, dateRight) === -sign; |
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var result = sign * (difference - isLastYearNotFull); // Prevent negative zero |
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return result === 0 ? 0 : result; |
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} |
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module.exports = exports.default; |