;
};
Checks every value in the upstream stream against a named validator, and
optionally sends valid and invalid values down different paths.
Where Converter changes a value, Validate judges it. Each validator is a small
named module that answers whether a value is acceptable and, when it is not,
why.
### Inputs
* **In** — the values to check.
### Outputs
* **Valid?** — one boolean per value, with its date and ID preserved. Wire it
into Switch's *check* port, into Assert, or into a Constant lookup.
* **Valid** — optional branch, taken when every value passed. Receives the
input unchanged.
* **Not valid** — optional branch, taken when any value failed. Receives the
input unchanged.
* **Reason** — optional. The validator's explanation for each value that
failed; empty when nothing did. Wire it into an Anomaly node's parameter to
tell the customer what was wrong.
Each branch you wire needs its own End node at the far side, the same way
Switch's branches do. Leave both branches unwired to use the node as a plain
test, and carry on from *Valid?*.
### Configuration
* **Validator** — pick one of the registered validators.
* **Options** — typed form rendered from the validator's declared params.
Validators that declare none show no options form.
* **Treat an empty value as** — *Valid* (the default) ignores a value that is
missing or blank, so a cleared field is not reported as bad data. *Not valid*
fails it with the reason "Value is empty".
### Tips
* The branch decision covers the whole timeline: one bad value in a field's
history sends the entire input down *Not valid*. *Valid?* still reports each
value separately, so use Switch on that port when you need per-value routing.
## Ports