const router = new VueRouter({
 routes: [
  // 动态路径参数 以冒号开头
  { path: '/user/:id', component: User, props: true }
 ]
})

<template>
 <div>{{ user.name }}</div>
</template>
<script>
 export default {
  name: 'User',
  props: ['id'],
  data() {
   return {data: {}};
  },
  watch: {
   id(id) {
    this.getUser(id);
   },
  },
  computed: {
   user() {
    return this.data[this.id] || {name: ''};
   },
  },
  methods: {
   getUser(id) {
    setTimeout(() => { // 假装异步
     this.data[id] = {id, name: '张' + id};
    }, 1000);
   },
  },
  mounted() {
   this.getUser(this.id);
  },
 };
</script>

<template>
 <div>
  <user
    v-for="_id in idList"
    v-show="_id === id"
    :id="_id"
    :key="_id"
  />
 </div>
</template>
<script>
 import User from './User.vue';

 export default {
  name: 'UserPage',
  components: {
   User,
  },
  props: ['id'],
  data() {
   return {
    idList: [this.id],
   };
  },
  watch: {
   id(id) {
    if (!this.idList.includes(id)) this.idList.push(id);
   },
  },
 };
</script>

{ path: '/user/:id', component: UserPage, props: true }