I'm trying to create a contact form. The form looks like this:

<form novalidate [formGroup]=contact (ngSubmit)=send()>

  <p>

    <label>Name

      <br>

      <input type=text class=input value= formControlName=name>

      <span class=error>Enter your name</span>

    </label>

  </p>

  <p>

    <label>E-mail

      <br>

      <input type=email class=input value= formControlName=email>

      <span class=error>It looks like this email is invalid</span>

    </label>

  </p>

  <p>

    <label>Phone

      <br>

      <input type=text class=input value= formControlName=telefone>

      <span class=error>It looks like this phone number is invalid</span>

    </label>

  </p>

  <p>

    <label>Message

      <br>

      <textarea type=text class=input value= formControlName=message></textarea>

      <span class=error>The message can't be empty</span>

    </label>

  </p>

  <p class=submit>

    <input type=submit name=submit class=bt value=Send>

  </p>

</form>

In this form only the message and the name and email or the phone number fields should be required.

I'm using a formBuilder class, so here's the TypeScript code:

this.contact = this.formBuilder.group({

  name: ['', Validators.required],

  email: ['', Validators.compose([/*Use custom validador??*/])],

  phone: ['', Validators.compose([/*Use custom validador??*/]],

  message: ['', Validators.required]

});

I tried using custom validators as a solution, but I could not figure out a solution. Any suggestions?