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+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault").default;
+Object.defineProperty(exports, "__esModule", {
+ value: true
+});
+exports.default = differenceInYears;
+var _index = _interopRequireDefault(require("../toDate/index.js"));
+var _index2 = _interopRequireDefault(require("../differenceInCalendarYears/index.js"));
+var _index3 = _interopRequireDefault(require("../compareAsc/index.js"));
+var _index4 = _interopRequireDefault(require("../_lib/requiredArgs/index.js"));
+/**
+ * @name differenceInYears
+ * @category Year Helpers
+ * @summary Get the number of full years between the given dates.
+ *
+ * @description
+ * Get the number of full years between the given dates.
+ *
+ * @param {Date|Number} dateLeft - the later date
+ * @param {Date|Number} dateRight - the earlier date
+ * @returns {Number} the number of full years
+ * @throws {TypeError} 2 arguments required
+ *
+ * @example
+ * // How many full years are between 31 December 2013 and 11 February 2015?
+ * const result = differenceInYears(new Date(2015, 1, 11), new Date(2013, 11, 31))
+ * //=> 1
+ */
+function differenceInYears(dirtyDateLeft, dirtyDateRight) {
+ (0, _index4.default)(2, arguments);
+ var dateLeft = (0, _index.default)(dirtyDateLeft);
+ var dateRight = (0, _index.default)(dirtyDateRight);
+ var sign = (0, _index3.default)(dateLeft, dateRight);
+ var difference = Math.abs((0, _index2.default)(dateLeft, dateRight));
+
+ // Set both dates to a valid leap year for accurate comparison when dealing
+ // with leap days
+ dateLeft.setFullYear(1584);
+ dateRight.setFullYear(1584);
+
+ // Math.abs(diff in full years - diff in calendar years) === 1 if last calendar year is not full
+ // If so, result must be decreased by 1 in absolute value
+ var isLastYearNotFull = (0, _index3.default)(dateLeft, dateRight) === -sign;
+ var result = sign * (difference - Number(isLastYearNotFull));
+ // Prevent negative zero
+ return result === 0 ? 0 : result;
+}
+module.exports = exports.default; \ No newline at end of file
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