Question

• Angular has a special syntax for keyboard events such as keyup.enter, but where's the doc of this ?
• how can i know ngForm has pro .form.valid?
• where defined each angular lib does ? (e.g. angular2/common )
• where can find event property ngModelChange def ?
• how can i know what pro which the directive instance has?

  e.g. 
    <input  #food="ngForm">
    <div [hidden]="food.valid"></div>