Choose against the task constraints
The invented brief asks for a date in YYYY-MM-DD format. A user types it character by character; a temporary prefix is not yet a completed answer. The final submission must validate every required value, even if a user never focused one of the fields.
| Condition | Check on field exit | Check on submit |
|---|---|---|
| Incomplete text during typing | Wait for field exit before a corrective error | Wait until submission attempt |
| Untouched required field | Field exit never happened | Final check catches missing answers |
| Several coordinated rules | Local result may not know the final form state | Evaluate against the submitted record |
Combine a considerate field-exit check for finished dates with complete submit validation. Avoid flashing a date error on the first digit. Where checking requires a remote request, handle pending and unavailable states separately from invalid input.
Follow the input state
| Moment | Value | Expected feedback |
|---|---|---|
| Typing | 2026-1 | No premature corrective error |
| Field left | 2026-11-31 | Date does not exist |
| Submit | Date blank | Required date missing |
If the blank date was never focused, can field-exit validation replace the final check?
Show the worked answer
No. No exit event occurred for that field. Submit validation must detect the missing required date regardless of earlier interactions.
Check the chosen interaction
- Typing an ordinary prefix does not repeatedly interrupt the user.
- An untouched required field is checked on submit.
- Unavailable remote validation is not labelled as an invalid date.