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MoiOvalle
Asked: 2020-02-19 21:09:45 +0800 CST 2020-02-19 21:09:45 +0800 CST

How can I make a FormControlName receive the Value of a Function in Angular and TypeScript?

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I am creating a patient management system with Angular and TypeScript and using FormControlNameas shown in the following code:

ngOnInit() {

    this.formularioPaciente = this.fb.group({
      TipoDocumento: ['', Validators.required],
      NumDocumento: ['', Validators.required],
      urlImg: [''],
      PNombre: ['', Validators.required],
      SNombre: [''],
      PApellido: ['', Validators.required],
      SApellido: ['', Validators.required],
      Genero: ['', Validators.required],
      FechaNacimiento: ['', Validators.required],
      Edad: [] ,
      EstadoCivil: ['', Validators.required],
      RH:['', Validators.required],
      EPS: [''],
      Departamento: ['', Validators.required],
      Municipio: ['', Validators.required],
      Zona: ['', Validators.required],
      Barrio: ['', Validators.required],
      Direccion: [''],
      Telefono: [''],
      Email: [''],
      NomPadre: [''],
      NomMadre: ['']   
    })
  }

The point is that to calculate the value of the Age Field I am using the following function using the moments js library:

calcularA(){
    this.formularioPaciente.value.FechaNacimiento = moment(new Date(this.formularioPaciente.value.FechaNacimiento));
    let fechafin = moment(Date.now());
    let diff = fechafin.diff(this.formularioPaciente.value.FechaNacimiento, 'year');
    return diff;
  }

How can I assign the Value of my function calcularA()to the field Edadof my FormControlNametry as follows:

Edad:[this.calcularA()]but it generates an error that tells me value is undefined, please help me I'm stuck.

html

1 Answers

  1. Best Answer

    You can modify the value of any FormControl using its method setValue:

    miFormulario.controls[<form_control_name>].setValue(...);

    or in a more elegant way (this is debatable, but it seems so to me):

    miFormulario.get(<form_control_name>).setValue(...);

    So in your case you can do the following:

    calcularA(){
    this.formularioPaciente.value.FechaNacimiento = moment(new Date(this.formularioPaciente.value.FechaNacimiento));
    let fechafin = moment(Date.now());
    let diff = fechafin.diff(this.formularioPaciente.value.FechaNacimiento, 'year');
    //con esto debería ser suficiente
    this.formularioPaciente.controls['Edad'].setValue(diff);
    return diff;
}
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