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require-ion-error-text

Require Ionic validation controls to provide an errorText source.

Requires Ionic controls participating in Angular Signal Forms validation to have a source for errorText.

Rule Details

The rule checks these Ionic controls in Angular template files:

  • ion-input
  • ion-textarea
  • ion-select
  • ion-checkbox
  • ion-radio-group
  • ion-toggle

By default, a supported control is checked only when it binds Angular Signal Forms with [formField]. It must use one of these error text sources:

  • A non-empty static errorText
  • A property-bound [errorText]
  • KitIonicFormField, when formFieldProvidesErrorText is enabled

[attr.errorText] is not accepted because Ionic exposes errorText as a component property. An empty or whitespace-only static value is also rejected. .spec.html files are ignored.

Options

{
  "rules": {
    "@rdlabo/rules/require-ion-error-text": [
      "error",
      {
        "formFieldProvidesErrorText": true,
        "checkAll": false,
        "ignoreReadonly": false
      }
    ]
  }
}

formFieldProvidesErrorText

  • Type: boolean
  • Default: false

When true, a supported control with [formField] may omit errorText because KitIonicFormField supplies it. Enable this option only after every relevant standalone component imports KitIonicFormField and the application installs provideKitIonicSignalForms().

This option declares that the adapter is installed; the rule does not inspect component imports or application providers. An explicit but empty errorText remains an error instead of falling back to the adapter.

checkAll

  • Type: boolean
  • Default: false

When true, the rule also checks supported controls without [formField]. This is opt-in because filters, search fields, and settings controls do not necessarily participate in validation.

ignoreReadonly

  • Type: boolean
  • Default: false

When both checkAll and ignoreReadonly are true, ion-input and ion-textarea with a literal readonly attribute are ignored. A dynamic [readonly] binding remains checked because the control may become editable at runtime.

Examples

Incorrect

<ion-input [formField]="fields.name"></ion-input>

<ion-textarea [formField]="fields.description" errorText="   "></ion-textarea>

<ion-select [formField]="fields.category" [attr.errorText]="categoryError"></ion-select>

With checkAll: true, a supported control without [formField] also requires an error text source:

<ion-toggle></ion-toggle>

Correct

<ion-input [formField]="fields.name" errorText="Name is required."></ion-input>

<ion-textarea [formField]="fields.description" [errorText]="descriptionError()"></ion-textarea>

With formFieldProvidesErrorText: true and the kit adapter installed:

<ion-select [formField]="fields.category"></ion-select>

With checkAll: true and ignoreReadonly: true:

<ion-input readonly></ion-input>

Unsupported controls such as ion-searchbar are outside the rule's scope:

<ion-searchbar [formField]="fields.query"></ion-searchbar>

When to enable

Enable this rule in Ionic Angular applications that use Ionic's errorText API for validation feedback. The default scope is appropriate for Angular Signal Forms applications because it checks validation-bound controls without imposing error messages on unrelated UI controls.

Use formFieldProvidesErrorText when the application delegates generic validation messages to @rdlabo/ionic-angular-kit. Use checkAll only when the application requires every supported Ionic control to declare an error text source.

The rule reports only and does not autofix application validation policy or adapter setup.

See also

Implementation

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