Generate a timestamped filename from a user-provided title.
The user-visible title (will be sanitized).
File extension including the dot (default '.json').
'.json'
A filename like my_awesome_note_2026-04-03_14-30-45.json.
my_awesome_note_2026-04-03_14-30-45.json
generateFilename('Piano Scales #3')// 'piano_scales_3_2026-04-03_14-30-45.json' Copy
generateFilename('Piano Scales #3')// 'piano_scales_3_2026-04-03_14-30-45.json'
Generate a timestamped filename from a user-provided title.