How to use empty value in select box?

Question

I have the massive of employees positions:

positions = [
    {
      id: '0',
      title: 'position0',
    },
    {
      id: '1',
      title: 'position1',
    },
    {
      id: '2',
      title: 'position2',
    },
    {
      id: '3',
      title: 'position3',
    },
];

I create reactive form. As you see, single field of this form is not initialized:

form: FormGroup = new FormGroup({
    position: new FormControl(),
});

Then i try to display this form using select box:

<div [formGroup]="form">
  <p-dropdown
    [options]="positions"
    formControlName="position"
    optionValue="id"
    optionLabel="title"
  >
  </p-dropdown>
</div>

I expect that this select box will be empty at the first load. However there is selected 'position0' value. It is a problem.

I need the displaying label like 'Please choose position'.

Here is the live example

Answer 1

We're missing placeholder attribute of p-dropdown component. Please add placeholder="Please choose position"

<p-dropdown
    [options]="positions"
    formControlName="position"
    placeholder="Please choose position" <!-- HERE
    optionValue="id"
    optionLabel="title"
>

Answer 2

I tried to quickly implement it and it worked as you wanted, your code looks ok I don't know what is missing but here is my implementation.

In app.component.ts

theForm: FormGroup;
positions = [
    {
      id: '0',
      title: 'position0',
    },
    {
      id: '1',
      title: 'position1',
    },
    {
      id: '2',
      title: 'position2',
    },
    {
      id: '3',
      title: 'position3',
    },
];
constructor(
 private fb: FormBuilder
) {}

ngOnInit() {
 this.theForm = this.fb.group({
      position: new FormControl(2)
    });
}

and in app.component.html:

<form [formGroup]="theForm">
 <p-dropdown optionLabel="title" placeholder="Please choose position" 
  [options]="positions" formControlName="position"></p-dropdown>
</form>

stackblitz

Answer 3

Add an object:

{
   id: '',
   title: 'Please select an option'
}

as the first one in the array.

You could also try mapping the same into the dynamic data.