Expose the error state of a property via the yielded contextual form component

[notmessenger]

The implementation will need to be fleshed out but the idea is that it will be possible to query the error state of properties in order to make decisions based off of them. For example, possibly,

{{#ef-form
  data=data
  errors=errors
  as |f|
}}
  {{f.input-text property="firstName"}}

  {{#if f.firstName.isValid}}
  {{/if}}

{{/ef-form}}

[notmessenger]

Given this data

theErrors: {
  bio: 'I should not be empty'
}

and template

{{#ef-form
  data=theProperties
  errors=theErrors
  as |f|
}}
{{/ef-form}}

this error state could be accessed via

{{#ef-form
  data=theProperties
  errors=theErrors
  as |f|
}}
  {{#if f.errorStates.bio}}
    Is in an error state
  {{/if}}
{{/ef-form}}

---

I am not aware of how to yield a dynamic hash property in https://github.com/ember-forge/ember-forge-ui/blob/form-components/app/templates/components/ef-form.hbs such that f.bio.isValid could be used, let alone f.bio. errorStates is an object that has all of this data though and can be exposed in such a way as it is a "known" thing on the ef-form component and is not dynamic.

We could create a helper that could give a cleaner syntax, though would likely need to be something along the lines of

{{#ef-form
  data=theProperties
  errors=theErrors
  as |f|
}}
  {{#if isValid "bio"}}
    Is in an error state
  {{/if}}
{{/ef-form}}

likely needing to also be namespaced, etc.

[davewasmer]

I'd suggest that in the form component you define a computed property that constructs whatever yielded API you need, then simply yield that property. This let's you leverage the full range of Javascript to build the API rather than just (hash ...)

[notmessenger]

@davewasmer There is a currently such a property being yielded like that, called errorStates. Are you suggesting to dynamically create additional computed properties, one for each error property value, that can then be yielded? Even if that isn't exactly what you are suggesting I'm not sure how to follow your suggestion to be able to have the f.bio.isValid with a computed property (regarding .isValid).

[davewasmer]

I guess it would have to be something like f.fields.bio.isValid, where fields would be a single computed property that would compute it all. Just a suggestion though - that might be prohibitive from a perf perspective

[notmessenger]

https://github.com/ember-forge/ember-forge-ui/commit/1c32bf3b5bcf517ad0eccc026dfebd2a48e5fafb exposes f.errorStates so that the example in https://github.com/ember-forge/ember-forge-ui/issues/157#issuecomment-245434383 is valid.

This, coupled with the error-state mixin, is enough for this issue to be closed for now. It can always be revisited if a different API is desired, but for now the functionality is provided.