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    Function isSameYear

    • Check if two dates are in the same calendar year.

      This function compares two dates and returns true if they fall within the same calendar year, regardless of month, day, or time components.

      Parameters

      • dateLeft: number | Date

        The first date as a Date object or timestamp (number)

      • dateRight: number | Date

        The second date as a Date object or timestamp (number)

      Returns boolean

      True if both dates are in the same year, false otherwise or if either date is invalid

      // Same year, different months
      const result = isSameYear(new Date(2024, 0, 1), new Date(2024, 11, 31));
      // Returns: true

      // Different years
      const result2 = isSameYear(new Date(2024, 11, 31), new Date(2025, 0, 1));
      // Returns: false

      // Same year, different times
      const result3 = isSameYear(
        new Date(2024, 5, 15, 14, 30),
        new Date(2024, 8, 20, 9, 45)
      );
      // Returns: true

      // Works with timestamps
      const result4 = isSameYear(Date.now(), Date.now());
      // Returns: true

      // Invalid dates return false
      const result5 = isSameYear(new Date("invalid"), new Date(2024, 0, 1));
      // Returns: false
      • Validates arguments before processing (consistent with library patterns)
      • Returns false for any invalid input (Invalid Date, NaN, Infinity, -Infinity)
      • Accepts both Date objects and numeric timestamps
      • Ignores month, day, and time components in the comparison
      • Uses diffYears internally to determine if the year difference is zero
      • Handles leap years, BC dates, and century boundaries correctly

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