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FormGroup

class

Tracks the value and validity state of a group of FormControl instances.

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class FormGroup extends AbstractControl {
  constructor(controls: { [key: string]: AbstractControl; }, validatorOrOpts?: ValidatorFn | AbstractControlOptions | ValidatorFn[], asyncValidator?: AsyncValidatorFn | AsyncValidatorFn[])
  controls: {...}
  registerControl(name: string, control: AbstractControl): AbstractControl
  addControl(name: string, control: AbstractControl): void
  removeControl(name: string): void
  setControl(name: string, control: AbstractControl): void
  contains(controlName: string): boolean
  setValue(value: { [key: string]: any; }, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  patchValue(value: { [key: string]: any; }, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  reset(value: any = {}, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  getRawValue(): any

  // inherited from forms/AbstractControl
  constructor(validator: ValidatorFn, asyncValidator: AsyncValidatorFn)
  value: any
  validator: ValidatorFn | null
  asyncValidator: AsyncValidatorFn | null
  parent: FormGroup | FormArray
  status: string
  valid: boolean
  invalid: boolean
  pending: boolean
  disabled: boolean
  enabled: boolean
  errors: ValidationErrors | null
  pristine: boolean
  dirty: boolean
  touched: boolean
  untouched: boolean
  valueChanges: Observable<any>
  statusChanges: Observable<any>
  updateOn: FormHooks
  root: AbstractControl
  setValidators(newValidator: ValidatorFn | ValidatorFn[]): void
  setAsyncValidators(newValidator: AsyncValidatorFn | AsyncValidatorFn[]): void
  clearValidators(): void
  clearAsyncValidators(): void
  markAsTouched(opts: { onlySelf?: boolean; } = {}): void
  markAllAsTouched(): void
  markAsUntouched(opts: { onlySelf?: boolean; } = {}): void
  markAsDirty(opts: { onlySelf?: boolean; } = {}): void
  markAsPristine(opts: { onlySelf?: boolean; } = {}): void
  markAsPending(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  disable(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  enable(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  setParent(parent: FormGroup | FormArray): void
  abstract setValue(value: any, options?: Object): void
  abstract patchValue(value: any, options?: Object): void
  abstract reset(value?: any, options?: Object): void
  updateValueAndValidity(opts: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void
  setErrors(errors: ValidationErrors, opts: { emitEvent?: boolean; } = {}): void
  get(path: string | (string | number)[]): AbstractControl | null
  getError(errorCode: string, path?: string | (string | number)[]): any
  hasError(errorCode: string, path?: string | (string | number)[]): boolean
}

Description

A FormGroup aggregates the values of each child FormControl into one object, with each control name as the key. It calculates its status by reducing the status values of its children. For example, if one of the controls in a group is invalid, the entire group becomes invalid.

FormGroup is one of the three fundamental building blocks used to define forms in Angular, along with FormControl and FormArray.

When instantiating a FormGroup, pass in a collection of child controls as the first argument. The key for each child registers the name for the control.

Constructor

Creates a new FormGroup instance.

constructor(controls: { [key: string]: AbstractControl; }, validatorOrOpts?: ValidatorFn | AbstractControlOptions | ValidatorFn[], asyncValidator?: AsyncValidatorFn | AsyncValidatorFn[])

Parameters
controls object

A collection of child controls. The key for each child is the name under which it is registered.

validatorOrOpts ValidatorFn | AbstractControlOptions | ValidatorFn[]

A synchronous validator function, or an array of such functions, or an AbstractControlOptions object that contains validation functions and a validation trigger.

Optional. Default is undefined.

asyncValidator AsyncValidatorFn | AsyncValidatorFn[]

A single async validator or array of async validator functions

Optional. Default is undefined.

Properties

Property Description
controls: { [key: string]: AbstractControl; } Declared in Constructor

A collection of child controls. The key for each child is the name under which it is registered.

Methods

Registers a control with the group's list of controls.

registerControl(name: string, control: AbstractControl): AbstractControl

Parameters
name string

The control name to register in the collection

control AbstractControl

Provides the control for the given name

Returns

AbstractControl

This method does not update the value or validity of the control. Use addControl instead.

Add a control to this group.

addControl(name: string, control: AbstractControl): void

Parameters
name string

The control name to add to the collection

control AbstractControl

Provides the control for the given name

Returns

void

This method also updates the value and validity of the control.

Remove a control from this group.

removeControl(name: string): void

Parameters
name string

The control name to remove from the collection

Returns

void

Replace an existing control.

setControl(name: string, control: AbstractControl): void

Parameters
name string

The control name to replace in the collection

control AbstractControl

Provides the control for the given name

Returns

void

Check whether there is an enabled control with the given name in the group.

contains(controlName: string): boolean

Parameters
controlName string

The control name to check for existence in the collection

Returns

boolean: false for disabled controls, true otherwise.

Reports false for disabled controls. If you'd like to check for existence in the group only, use get instead.

Sets the value of the FormGroup. It accepts an object that matches the structure of the group, with control names as keys.

setValue(value: { [key: string]: any; }, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void

Parameters
value object

The new value for the control that matches the structure of the group.

options object

Configuration options that determine how the control propagates changes and emits events after the value changes. The configuration options are passed to the updateValueAndValidity method.

  • onlySelf: When true, each change only affects this control, and not its parent. Default is false.
  • emitEvent: When true or not supplied (the default), both the statusChanges and valueChanges observables emit events with the latest status and value when the control value is updated. When false, no events are emitted.

Optional. Default is {}.

Returns

void

Throws

Error When strict checks fail, such as setting the value of a control that doesn't exist or if you exclude a value of a control that does exist.

Usage Notes

Set the complete value for the form group
const form = new FormGroup({
  first: new FormControl(),
  last: new FormControl()
});

console.log(form.value);   // {first: null, last: null}

form.setValue({first: 'Nancy', last: 'Drew'});
console.log(form.value);   // {first: 'Nancy', last: 'Drew'}

Patches the value of the FormGroup. It accepts an object with control names as keys, and does its best to match the values to the correct controls in the group.

patchValue(value: { [key: string]: any; }, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void

Parameters
value object

The object that matches the structure of the group.

options object

Configuration options that determine how the control propagates changes and emits events after the value is patched.

  • onlySelf: When true, each change only affects this control and not its parent. Default is true.
  • emitEvent: When true or not supplied (the default), both the statusChanges and valueChanges observables emit events with the latest status and value when the control value is updated. When false, no events are emitted. The configuration options are passed to the updateValueAndValidity method.

Optional. Default is {}.

Returns

void

It accepts both super-sets and sub-sets of the group without throwing an error.

Usage Notes

Patch the value for a form group
const form = new FormGroup({
   first: new FormControl(),
   last: new FormControl()
});
console.log(form.value);   // {first: null, last: null}

form.patchValue({first: 'Nancy'});
console.log(form.value);   // {first: 'Nancy', last: null}

Resets the FormGroup, marks all descendants are marked pristine and untouched, and the value of all descendants to null.

reset(value: any = {}, options: { onlySelf?: boolean; emitEvent?: boolean; } = {}): void

Parameters
value any

Resets the control with an initial value, or an object that defines the initial value and disabled state.

Optional. Default is {}.

options object

Configuration options that determine how the control propagates changes and emits events when the group is reset.

  • onlySelf: When true, each change only affects this control, and not its parent. Default is false.
  • emitEvent: When true or not supplied (the default), both the statusChanges and valueChanges observables emit events with the latest status and value when the control is reset. When false, no events are emitted. The configuration options are passed to the updateValueAndValidity method.

Optional. Default is {}.

Returns

void

You reset to a specific form state by passing in a map of states that matches the structure of your form, with control names as keys. The state is a standalone value or a form state object with both a value and a disabled status.

Usage Notes

Reset the form group values
const form = new FormGroup({
  first: new FormControl('first name'),
  last: new FormControl('last name')
});

console.log(form.value);  // {first: 'first name', last: 'last name'}

form.reset({ first: 'name', last: 'last name' });

console.log(form.value);  // {first: 'name', last: 'last name'}
Reset the form group values and disabled status
const form = new FormGroup({
  first: new FormControl('first name'),
  last: new FormControl('last name')
});

form.reset({
  first: {value: 'name', disabled: true},
  last: 'last'
});

console.log(this.form.value);  // {first: 'name', last: 'last name'}
console.log(this.form.get('first').status);  // 'DISABLED'

The aggregate value of the FormGroup, including any disabled controls.

getRawValue(): any

Parameters

There are no parameters.

Returns

any

Retrieves all values regardless of disabled status. The value property is the best way to get the value of the group, because it excludes disabled controls in the FormGroup.

Usage notes

Create a form group with 2 controls

const form = new FormGroup({
  first: new FormControl('Nancy', Validators.minLength(2)),
  last: new FormControl('Drew'),
});

console.log(form.value);   // {first: 'Nancy', last; 'Drew'}
console.log(form.status);  // 'VALID'

Create a form group with a group-level validator

You include group-level validators as the second arg, or group-level async validators as the third arg. These come in handy when you want to perform validation that considers the value of more than one child control.

const form = new FormGroup({
  password: new FormControl('', Validators.minLength(2)),
  passwordConfirm: new FormControl('', Validators.minLength(2)),
}, passwordMatchValidator);


function passwordMatchValidator(g: FormGroup) {
   return g.get('password').value === g.get('passwordConfirm').value
      ? null : {'mismatch': true};
}

Like FormControl instances, you choose to pass in validators and async validators as part of an options object.

const form = new FormGroup({
  password: new FormControl('')
  passwordConfirm: new FormControl('')
}, { validators: passwordMatchValidator, asyncValidators: otherValidator });

Set the updateOn property for all controls in a form group

The options object is used to set a default value for each child control's updateOn property. If you set updateOn to 'blur' at the group level, all child controls default to 'blur', unless the child has explicitly specified a different updateOn value.

const c = new FormGroup({
  one: new FormControl()
}, { updateOn: 'blur' });

© 2010–2019 Google, Inc.
Licensed under the Creative Commons Attribution License 4.0.
https://angular.io/api/forms/FormGroup