vue / cli3 + typescript watch prop component computed in Usage

    The first step: introduction:

{the Component Import, Prop, Watch, Vue} from 'VUE-Property-Decorator'; 
// Note points: the first letter is capitalized 

Step: Usage 
1.component

@Component ({ 
Components: { 
     // component name 
  } 
}) 
Export default class formall the extends Vue { 
2.prop 
@Prop () Private visible: = Boolean to false;

// visible data transfer from a parent 

3.computed 

Columns GET Private () { 
  // calculated data 
}

4.watch 

@Watch ( 'you to listen attributes') 
Watchdata (newVal, oldVal) { 

    the console.log ( "newVal", newVal, "oldVal", oldVal); 
// you logical operation processing

};

}