The beauty of crafting intricate forms with Angular's reactive nested

Question

The beauty of crafting intricate forms with Angular's reactive nested

In my Angular project, I am exploring the concept of nesting multiple reactive forms within different components.

For instance, I have a component called NameDescComponent that includes a form with two inputs - one for name and one for description, along with a submit button.

The goal is to reuse this component across various pages and forms. Here's a snippet of the HTML code for the component:

<form [formGroup]="nameDescForm" (ngSubmit)="customEmit()">
    <div fxLayout="row" fxLayoutGap="10px" fxFlex>
      <mat-form-field>
        <input matInput placeholder="Name" formControlName="name">
      </mat-form-field>
      <mat-form-field fxFlex>
        <input matInput placeholder="Description" formControlName="description">
      </mat-form-field>
    </div>
    <div fxLayout="column" fxLayoutGap="10px">
      <button type="submit" mat-raised-button color="primary">
        {{buttonText}}
      </button>
      <div>
      </div>
    </div>
  </form>

And here's an excerpt from the corresponding TypeScript file:

public nameDescForm: FormGroup;

@Input() public buttonText: string;
@Output() public save: EventEmitter<any> = new EventEmitter<any>();
@Output() public nameDescFormEmit: EventEmitter<FormGroup> = new EventEmitter<FormGroup>();

constructor(fb: FormBuilder) {
this.nameDescForm = fb.group({
'name': ['', Validators.required],
'description': ['']
});
}

public ngOnInit() {
console.log(this.nameDescForm);
this.nameDescFormEmit.emit(this.nameDescForm);
}

public customEmit() {
this.save.emit();
}

Furthermore, in a separate page where I include the NameDescComponent, I embed it within another form like so:

<form [formGroup]="parentForm" (ngSubmit)="customEmit()">

  <app-name-description (nameDescFormEmit)="getNameDescForm($event)" buttonText="Save" (save)="save()"></app-name-description>

  <input type="test" formControlName="test">

</form>

Currently, I pass the nameDescFrom data from its component to the ParentComponent using Output and EventEmitter. Although this approach works, I find myself having to independently manage both forms' validity during submission.

I'm curious if there might be a more efficient way to handle this, perhaps accessing the nameDescFrom directly within the parent form?

Thank you

javascript angular typescript angular-reactive-forms angular-forms

Answer 1

Answer №1

If you want to combine your form with nested forms and streamline the validation process for all of them, you can utilize the formbuilder to construct the entire model object structure within the main form component. Next, in the HTML template, include custom elements for the sub-forms (e.g., <nested-form>), which will display the nested forms.

Check out this example: https://stackblitz.com/edit/angular-m5fexe)

Helpful Angular documentation links:

Code :

export class Form1Component  {
  @Input() name: string;

  public dummyForm: FormGroup;

  constructor(
      private _fb: FormBuilder,
  ) {
      this.createForm();
  }

  createForm() {
    this.dummyForm = this._fb.group({
      username: ['username', Validators.required],
      nestedForm: this._fb.group({        
        complement1: ['complement1', Validators.required],
        complement2: ['complement2', Validators.required],
      })
    });
  }

  submit() {
    if (this.dummyForm.valid) {
      console.log('form AND subforms are valid', this.dummyForm.value);
    } else {
      console.warn('form AND/OR subforms are invalid', this.dummyForm.value);
    }
  }
}

Template for the Form1Component :

<form [formGroup]="dummyForm" (ngSubmit)="submit()">    
    <div>
      <label for="username">Root Input</label>
      <input type="text" id="username" formControlName="username"/>
    </div>
    <nested-form [parentForm]="dummyForm"></nested-form>
    <button>Send</button>    
  </form>

Nested form code:

export class NestedFormComponent {
  @Input()
  public parentForm: FormGroup;
}

Nested form template :

<form [formGroup]="parentForm">
    <div formGroupName="nestedForm">
      <div>
        <label for="complement1">Nested input 1</label>
        <input type="text" formControlName="complement1"/>
      </div>
      <div>
        <label for="complement1">Nested input 1</label>
        <input type="text" formControlName="complement2"/>
      </div>
    </div>
  </form>

Answer 2

If you want to combine your form with nested forms and streamline the validation process for all of them, you can utilize the formbuilder to construct the entire model object structure within the main form component. Next, in the HTML template, include custom elements for the sub-forms (e.g., <nested-form>), which will display the nested forms.

Check out this example: https://stackblitz.com/edit/angular-m5fexe)

Helpful Angular documentation links:

Code :

export class Form1Component  {
  @Input() name: string;

  public dummyForm: FormGroup;

  constructor(
      private _fb: FormBuilder,
  ) {
      this.createForm();
  }

  createForm() {
    this.dummyForm = this._fb.group({
      username: ['username', Validators.required],
      nestedForm: this._fb.group({        
        complement1: ['complement1', Validators.required],
        complement2: ['complement2', Validators.required],
      })
    });
  }

  submit() {
    if (this.dummyForm.valid) {
      console.log('form AND subforms are valid', this.dummyForm.value);
    } else {
      console.warn('form AND/OR subforms are invalid', this.dummyForm.value);
    }
  }
}

Template for the Form1Component :

<form [formGroup]="dummyForm" (ngSubmit)="submit()">    
    <div>
      <label for="username">Root Input</label>
      <input type="text" id="username" formControlName="username"/>
    </div>
    <nested-form [parentForm]="dummyForm"></nested-form>
    <button>Send</button>    
  </form>

Nested form code:

export class NestedFormComponent {
  @Input()
  public parentForm: FormGroup;
}

Nested form template :

<form [formGroup]="parentForm">
    <div formGroupName="nestedForm">
      <div>
        <label for="complement1">Nested input 1</label>
        <input type="text" formControlName="complement1"/>
      </div>
      <div>
        <label for="complement1">Nested input 1</label>
        <input type="text" formControlName="complement2"/>
      </div>
    </div>
  </form>

Answer 3

Answer №2

If you want to enhance your Angular forms, consider using a custom form control to streamline the process.

Essentially, a custom component acts as a connection point between the main form and any nested forms, ensuring smooth communication between the two. By listening for changes in the nested form, the custom component can update its value accordingly. Despite containing values from multiple nested form controls, the parent form will view the custom control as a single entity.

To implement this functionality, the custom component must adhere to the ControlValueAccessor interface provided by Angular. This allows for seamless management of the custom control's state, including aspects like value, validity, touch status, and more. With this approach, the parent form can interact with the custom control just like any other form element.

To learn more about this technique, check out these resources:

https://medium.com/@majdasab/implementing-control-value-accessor-in-angular-1b89f2f84ebf

Answer 4

If you want to enhance your Angular forms, consider using a custom form control to streamline the process.

Essentially, a custom component acts as a connection point between the main form and any nested forms, ensuring smooth communication between the two. By listening for changes in the nested form, the custom component can update its value accordingly. Despite containing values from multiple nested form controls, the parent form will view the custom control as a single entity.

To implement this functionality, the custom component must adhere to the ControlValueAccessor interface provided by Angular. This allows for seamless management of the custom control's state, including aspects like value, validity, touch status, and more. With this approach, the parent form can interact with the custom control just like any other form element.

To learn more about this technique, check out these resources:

https://medium.com/@majdasab/implementing-control-value-accessor-in-angular-1b89f2f84ebf

The beauty of crafting intricate forms with Angular's reactive nested

Answer №1

Answer №2

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