ngx-reactive-forms-utils

Reactive forms in Angular are a great way to manage forms. This library provides utilities that make it easier to work with reactive forms.

Utilities that are provided include:

• Easy validation error display
• Some common custom validators

To get started, import the NgxReactiveFormsUtilsModule in your app's AppModule.

Validation Error Display

Error messages are provided for the following common errors out of the box:

• required
• minlength
• maxlength
• min
• max
• email
• number
• minAge
• maxAge

These error messages can be overwritten with the addCustomErrorMessage function:

addCustomErrorMessage('required', () => 'This is a new required field message');

If you have a custom error message that you need to show, you can add it with the same function as demonstrated above:

addCustomErrorMessage('newCustomError', () => 'This is a new custom error message');

The ngx-control-errors-display component will show the validation errors for a given form control automatically. You can wrap your input in the component, and any relevant errors will be displayed if necessary. There are a few inputs:

• containerClasses: a string of css classes to apply to the container element that wraps the projected content and the necessary error messages
• errorClasses: a string of css classes to apply to the error message elements
• rules: a list of rules for when to check for errors on the form control. it defaults to ['touched']

<form class="mx-auto flex flex-col gap-4 justify-center items-center" [formGroup]="form">
  <div class="flex gap-2 items-start">
    <label class="pt-2" for="name">Name: </label>
    <ngx-control-errors-display errorClasses="error-message">
      <input type="text" formControlName="name" />
    </ngx-control-errors-display>
  </div>
  <ngx-control-errors-display errorClasses="error-message">
    <div class="flex gap-2 items-center">
      <label for="email">Email: </label><input type="text" formControlName="email" />
    </div>
  </ngx-control-errors-display>
  <ngx-control-errors-display errorClasses="error-message">
    <div class="flex gap-2 items-center">
      <label for="age">Age: </label><input type="number" formControlName="age" />
    </div>
  </ngx-control-errors-display>
</form>

Custom Validators

The Angular reactive forms module provides a good list of default Validators for form controls, but there are some that would be convenient that are not present. This library adds those validators:

• phoneNumber: validates a phone number
• number: validates that the value is a number
• validZipCode: validates a US zip code
• confirmStringMatch: validates that field 1 and field 2 have the same value
• minAge: validates that the age passed in to the control is at least the provided age
• maxAge: validates that the age passed in to the control is no greater than the provided age