# `MishkaGervaz.Form.Web.Events.ValidationHandler`
[🔗](https://github.com/mishka-group/mishka_gervaz/blob/v0.0.1-alpha.3/lib/mishka_gervaz/form/web/events/validation_handler.ex#L1)

Handles form validation (phx-change events).

## Overridable Functions

- `validate/3` - Validate form params and update form state
- `build_errors/1` - Extract errors from form

## User Override

    defmodule MyApp.Form.ValidationHandler do
      use MishkaGervaz.Form.Web.Events.ValidationHandler

      def validate(state, params, socket) do
        # Add custom validation
        super(state, params, socket)
      end
    end

See `MishkaGervaz.Form.Web.Events`,
`MishkaGervaz.Form.Web.Events.Helpers` (for `parse_typed_params/2`),
and the sibling sub-handlers.

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*Consult [api-reference.md](api-reference.md) for complete listing*