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

Shared helpers for `MishkaGervaz.Form.Web.Events` and its sub-handlers.

Two reasons these live here rather than inside each sub-handler's
`__using__` macro:

1. **Reuse across sub-handlers and user overrides.** A user module that
   overrides `submit/3` (via `use Events.SubmitHandler`) can call any
   helper here without redefining it.
2. **Smaller compiled bytecode per consumer.** Pure helpers compile
   once in this module rather than into every consumer's beam.

Three groups:

- **Typed-param helpers** (`parse_typed_params/2`,
  `sanitize_typed_params/2`) — dispatch through `field.type_module`
  when set; pass through otherwise.
- **Sanitization helpers** (`sanitize_string/1`,
  `sanitize_list_item/2`) — extracted from `SanitizationHandler`'s
  `__using__` macro.
- **Upload helpers** (`merge_uploaded_files/4`) — extracted from
  `SubmitHandler`'s `__using__` macro.

See `MishkaGervaz.Form.Web.Events`,
`MishkaGervaz.Form.Web.Events.SanitizationHandler`,
`MishkaGervaz.Form.Web.Events.SubmitHandler`,
`MishkaGervaz.Form.Web.Events.ValidationHandler`, and the sibling
sub-handlers.

# `validate_typed_params`

```elixir
@spec validate_typed_params([map()], map()) :: [{atom(), String.t()}]
```

Runs each field's `FieldType.validate/2` over `params` and returns a list
of `{field_atom, message}` pairs ready to merge into an AshPhoenix.Form's
`errors` keyword list. Fields whose type module doesn't implement
`validate/2` (detected via the cached `:custom_validate?` flag) are
skipped.

---

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