Function getSeconds

getSeconds(date: number | Date): number
Get the seconds of the given date.

This function validates arguments before processing and returns the seconds (0-59) of the given date. Returns NaN for invalid input.
Parameters
- date: number | Date
  The base date as a Date object or timestamp (number)
Returns number
The seconds as a number (0-59), or NaN if invalid
Example
```
// Get seconds from Date object
const result = getSeconds(new Date(2025, 0, 15, 10, 30, 45));
// Returns: 45

// Get seconds from timestamp
const result2 = getSeconds(1704067245000); // 2024-01-01T00:00:45Z
// Returns: 45

// Start of minute
const result3 = getSeconds(new Date(2024, 0, 1, 10, 30, 0));
// Returns: 0

// End of minute
const result4 = getSeconds(new Date(2024, 0, 1, 10, 30, 59));
// Returns: 59

// Invalid date returns NaN
const result5 = getSeconds(new Date("invalid"));
// Returns: NaN
```
Remarks
- Validates arguments before conversion (consistent with library patterns)
- Accepts both Date objects and numeric timestamps
- Returns NaN for: Invalid Date, NaN, Infinity, -Infinity
- Returns the seconds in the local timezone
- Seconds are always in the range 0-59
- Defined in getSeconds/index.ts:42