data() {

return {

options2: [{

label: '江苏',

cities: [{label:'南京'},{label:'a'},{label:'b'}]

}, {

label: '浙江',

cities: [{label:'杭州'}]

}],

props: {

value: 'label',

children: 'cities'

}

};

},

methods: {

handleItemChange(val) {

/* console.log('active item:', val);

console.log(val[0]) */

setTimeout(_ => {

this.options2.map((item,index)=>{

if(item.label==val[0]){

/* console.log(item.cities) */

this.options2[index].cities=

item.cities

}

})

}, 300);

}

}