touched and valid using reactive forms in Angular

How can i use the touched and valid properties using reactive forms in angular 4. I've used in template driven forms and you can just put this <span class="text-muted" *ngIf="!fname.valid && fname.touched"> Please enter a valid first name</span> below the input field. I've also learned that reactive forms would be better since you have to write the logic in the component.ts. So i want it to implement in the reactive form and i'm stuck on how to use the touched and valid properties.

html
​

<form [formGroup]="form" (ngSubmit)="onSignIn(form)">
<div class="form-group">
<input type="text" class="form-control" id="email" placeholder="Enter email" formControlName="email">
</div>
<div class="form-group">
<input type="password" class="form-control" id="password" placeholder="Password" formControlName="password">
</div><button class="btn btn-primary btn-block" type="submit" [disabled]="!form.valid">Sign In</button>
</form>

ts
​

ngOnInit() {
this.form = this.formBuilder.group({
email: [null, [Validators.required, Validators.email]],
password: [null, Validators.required],
});
}

onSignIn(form: FormGroup){
const email = form.value.email;
const password = form.value.password;
this.authService.loginUser(email, password)
.subscribe(
data => {
this.router.navigate(['/settings']);
alert("Login Successful");
console.log(data);
},
error => {
alert("Invalid Email or Password");
console.log(error);
});
}

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