How to apply TypeScript classes in Vue projects

import {Component,Vue} from 'vue-property-decorator'; 
import {componentA,componentB} from '@/components'; 
 
 @Component({ 
    components:{ 
        componentA, 
        componentB, 
    }, 
    directives: { 
        focus: 
            // Definition of instruction inserted: function (el) { 
                el.focus() 
            } 
        } 
    } 
}) 
export default class YourCompoent extends Vue{ 
    
} 

@Component 
export default class HelloDecorator extends Vue { 
    count: number = 123 // The class attribute is equivalent to the previous data 
 
    add(): number { // The class method is the same as the previous method this.count + 1 
    } 
 
    // Get the calculated attribute get total(): number { 
      return this.count + 1 
    } 
 
    // Set the calculated properties set total(param:number): void { 
      this.count = param 
    } 
} 

import {Component,Vue,Prop} from vue-property-decorator; 
 
@Component 
export default class YourComponent extends Vue { 
    @Prop(String) 
    propA: string; 
     
    @Prop([String,Number]) 
    propB:string|number; 
     
    @Prop({ 
     type: String, // type: [String , Number] 
     default: 'default value', // usually a String or Number 
      //If it is an object or array. Default value is returned from a factory function // default: () => { 
      // return ['a','b'] 
      // } 
     required: true, 
     validator: (value) => { 
        return [ 
          'InProcess', 
          'Settled' 
        ].indexOf(value) !== -1 
     } 
    }) 
    propC: string; 
} 

import { Vue, Component, Watch } from 'vue-property-decorator' 
 
@Component 
export default class YourComponent extends Vue { 
  @Watch('child') 
  onChildChanged(val: string, oldVal: string) {} 
 
  @Watch('person', { immediate: true, deep: true }) 
  onPersonChanged1(val: Person, oldVal: Person) {} 
 
  @Watch('person') 
  onPersonChanged2(val: Person, oldVal: Person) {} 
} 

import {Vue, Component, Emit} from 'vue-property-decorator'; 
    @Component({}) 
    export default class Some extends Vue{ 
        mounted(){ 
            this.$on('emit-todo', function(n) { 
                console.log(n) 
            }) 
            this.emitTodo('world'); 
        } 
        @Emit() 
        emitTodo(n: string){ 
            console.log('hello'); 
        } 
    }