Function formatSignedInt

formatSignedInt(n: number, min_len?: number, fill_string?: string): string
Formats a number with an explicit sign prefix (+, -, or ± for zero).
Parameters
- n: number
  The number to format.
- Optionalmin_len: number
  Minimum UTF-16 length of the numeric part, excluding the sign.
- Optionalfill_string: string
  Padding string (default: ' ').
Returns string
The formatted string with sign prefix.
Remarks
Uses the number's string representation without rounding or truncating it to an integer. Padding is applied before the numeric part but after the sign; an empty padding string adds nothing. Both positive and negative zero use ±.
Example
```
formatSignedInt(42);        // "+42"
formatSignedInt(-5);        // "-5"
formatSignedInt(0);         // "±0"
formatSignedInt(5, 3, '0'); // "+005"
```
- Defined in string/format.ts:55