javascript
const cleaned = str.replace(/^\s*$/gm, '').replace(/\n+/g, '\n').trim();
python
import re
cleaned = re.sub(r'^\s*$\n', '', text, flags=re.MULTILINE).strip()
go
import "regexp"
re := regexp.MustCompile(`(?m)^\s*$\n`)
cleaned := strings.TrimSpace(re.ReplaceAllString(text, ""))