I'm currently working on a major release 0.3.0. Branch is in https://github.com/voliva/formicary/tree/v3.

I published the first preview to npm as 0.3.0-beta.0. Please note the API is still subject to change before finishing, so use it at your own risk.

What this release addresses mainly is:

• Context-based API (as an alternative to without context).
• Clarify many API methods which had confusing names, were hard to understand or were inconsistent.
• Leverage new typescript capabilities.
• i18n support on validators.

Changes

Features

• Context
  • Added FormicaryContext.Provider to avoid prop-drilling if desired
  • Now every hook optionally can have the formRef parameter omitted. If it's omitted, it will grab the formRef from the context instead.
  • To help with typescript support, there's a new helper method createKeyFn<FormModel>() that will give a function that should autocomplete the paths for FormModel, plus providing the correct type for each parameter.
• Key selectors
  • String-based key selectors have now typescript support. Typescript should auto-complete the paths when using them.
  • useErrors will now return a type-safe dictionary of elements when using the paths overload (e.g. useErrors(form, 'name', 'age') returns type { name: Error, age: Error }).
• Undefined values
  • useControl and useControlStateless now don't require an initial value: The value will be undefined by default.
  • All methods that set the value of a field accept undefined to reset them as empty.
  • All methods that get a value of a field can potentially return undefined for type safety, except getFormValue to make matters simple. Be aware some values could be undefined, although it should not happen if validation rules are set up and form is marked as valid.
• New hook useFieldChanges(key, cb: (value, isInitial) => void) that will call the call-back every time that the field changes its value (it will also call it with the initial value setting isInitial to true)
• New commands getInitialValue and getFormInitialValue to get the initial value of a field or the form respectively.
• New command getAllErrors to get a map with the fields that fail validation.
• Validators
  • All validator constructors have a consistent shape: They are functions that return a validator (e.g. isRequired() isAtLeast(5))
  • Validation error messages can now be customized through setValidatorMessages or through an optional parameter when creating it.
  • Clarified the return type of a validator: It either returns true (value is valid) or a list of error messages.
• Now the type for FormRef<FormModel> is assignable to another variable with a subtype. This is particularly useful for subcomponents that only take a few properties of the whole model.

Breaking

• useInput
  • useInput now requires the key. It will ignore the name attribute of the element it gets attached to.
  • This provides better type safety with validators, and make it easier to understand what property the input is going to be attached to.
• Hooks with multiple key selectors (useErrors, etc.).
  • To improve type safety, now hooks that took arrays of keys should have them spread as parameters. E.g. useError(form, ['name', 'age']) should become useErrors(form, 'name', 'age').
  • The selector function validator is unaffected from this change (E.g. useError(form, v => [v.name, v.age])) is alright, but won't have the new enhanced type safety.
• Validators
  • isRequired, isNumber and isInteger must now be called to get the actual validator.
  • Validators that are not isRequired will now return the value is valid if the value is nil, otherwise it would not be possible to make e.g. an optional numeric field. To migrate, they can be composed with pipeValidators(isRequired(), {{validator}}).
  • Validators can't return false now when the value is invalid. On that case they must return a list of errors messages.
• Renames
  • useWatch renamed to useFieldValue - Reason: it's more descriptive of what it's returning.
  • useFormChanges renamed to useFormValue - Reason: it's more descriptive of what it's returning.
  • useControlSubscription renamed to useControlStateless - Reason: the name was misleading, it's not creating a Subscription, but returning something that you can subscribe to without using a state.
  • readField renamed to getFieldValue - Reason: More descriptive and consistent with the setFieldValue counterpart.
  • readForm renamed to getFormValue - Reason: More descriptive and consistent with the setFormValue counterpart.
• The type for FormRef is now opaque. It can still be used to pass the formRef around, but its properties are private and can't be accessed. Use exported methods instead.

TODO

• getInitialValue
• getAllErrors
• investigate arrays
• add test to verify initialValue on useForm prevails over initialValue on useInput
• Define what happens when a field gets unmounted: Is it saved? validators still apply? is it removed?
  -> By default, value is retained. Option to have it removed on unmount.

(Release open to feedback)