export default {
    data() {
        return {
            item: ''
        }
    },
    watch: {
        item(now, before){
            let remove = before.filter(x => now.indexOf(x) == -1);
            let add = now.filter(x => before.indexOf(x) == -1);
            /* 显示字符串或数组元素的增加和减少 */
            console.log(add, remove);
        }
    }
}