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/Angular 7

FormArrayName

directive

Syncs a nested FormArray to a DOM element.

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See also

NgModule

Selectors

Properties

Property Description
@Input('formArrayName')name: string

Tracks the name of the FormArray bound to the directive. The name corresponds to a key in the parent FormGroup or FormArray.

control: FormArray Read-only.

The FormArray bound to this directive.

formDirective: FormGroupDirective | null Read-only.

The top-level directive for this group if present, otherwise null.

path: string[] Read-only.

Returns an array that represents the path from the top-level form to this control. Each index is the string name of the control on that level.

validator: ValidatorFn | null Read-only.

Synchronous validator function composed of all the synchronous validators registered with this directive.

asyncValidator: AsyncValidatorFn | null Read-only.

Async validator function composed of all the async validators registered with this directive.

Inherited from ControlContainer

Inherited from AbstractControlDirective

Description

This directive is designed to be used with a parent FormGroupDirective (selector: [formGroup]).

It accepts the string name of the nested FormArray you want to link, and will look for a FormArray registered with that name in the parent FormGroup instance you passed into FormGroupDirective.

Example

import {Component} from '@angular/core';
import {FormArray, FormControl, FormGroup} from '@angular/forms';

@Component({
  selector: 'example-app',
  template: `
    <form [formGroup]="form" (ngSubmit)="onSubmit()">
      <div formArrayName="cities">
        <div *ngFor="let city of cities.controls; index as i">
          <input [formControlName]="i" placeholder="City">
        </div>
      </div>
      <button>Submit</button>
    </form>
    
    <button (click)="addCity()">Add City</button>
    <button (click)="setPreset()">Set preset</button>
  `,
})
export class NestedFormArray {
  form = new FormGroup({
    cities: new FormArray([
      new FormControl('SF'),
      new FormControl('NY'),
    ]),
  });

  get cities(): FormArray { return this.form.get('cities') as FormArray; }

  addCity() { this.cities.push(new FormControl()); }

  onSubmit() {
    console.log(this.cities.value);  // ['SF', 'NY']
    console.log(this.form.value);    // { cities: ['SF', 'NY'] }
  }

  setPreset() { this.cities.patchValue(['LA', 'MTV']); }
}

Methods

A lifecycle method called when the directive's inputs are initialized. For internal use only.

ngOnInit(): void

Parameters

There are no parameters.

Returns

void

Throws

Error If the directive does not have a valid parent.

A lifecycle method called before the directive's instance is destroyed. For internal use only.

ngOnDestroy(): void

Parameters

There are no parameters.

Returns

void

Inherited from AbstractControlDirective

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Licensed under the Creative Commons Attribution License 4.0.
https://v7.angular.io/api/forms/FormArrayName