articles-form.component.html

<form [formGroup]="articleForm" (ngSubmit)="onSubmit()">
    <div class="input-field col s12">
        <input id="title" formControlName="title" type="text">
        <label for="title" class="active">Titulo</label>
    </div>
    <div class="input-field col s12">
            <textarea id="body" formControlName="body" class="materialize-textarea"></textarea>
            <label for="body">Agregar el contenido</label>
    </div>
    <p>Form value: {{ articleForm.value | json }}</p>
    <button type="submit" >Guardar</button>
</form>