vue-router始终创建一个新的Component实例

Question

我在vue-router中发现了一个问题,它引发了我很多.总是当我在我的路线之间切换时,会创建一个新的组件实例.此外,旧实例不会被删除并在后台运行!

我希望当我打开一条路线时,旧组件将被销毁或停止运行.

有解决方法来解决这个问题吗？

这是一个小提琴:https://jsfiddle.net/4xfa2f19/5885/

let foo = {
    template: '<div>Foo</div>',
    mounted() {
        console.log('Mount Foo with uid: ' + this._uid);
        setInterval(() => {console.log('Instance ' + this._uid + ' of Foo is running')}, 500);
    }
};

let bar = {
    template: '<div>Bar</div>',
    mounted() {
        console.log('Mount Bar with uid: ' + this._uid);
        setInterval(() => {console.log('Instance ' + this._uid + ' of Bar is running')}, 500);
    }
};


const router = new VueRouter({
    routes: [
        { path: '/user/foo', component: foo },
        { path: '/user/bar', component: bar }
    ]
});


const app = new Vue({ router }).$mount('#app');

Answer 1

有两种方法可以解决这个问题:

正确清理destroy钩子

如果您使用任何外部事件侦听器,例如setInterval,addEventListener等等,您还需要在组件被销毁时取消注册它们,例如:

{
    name: '...',
    template: '...',
    data() {
        return {
            interval: undefined,
            timeout: undefined
        };
    },
    mounted() {
        interval = setInterval(() => {console.log('Instance ' + this._uid + ' of myself is running')}, 500);
        timeout = setTimeout(() => {console.log('Instance ' + this._uid + ' of myself is running')}, 500);
        document.addEventListener('click', this.onOutsideClick);
    },
    beforeDestroy() {
        // Cleanup interval
        clearInterval(interval);
        // Cleanup any pending timeouts
        clearTimeout(timeout);
        // Cleanup any event listeners outside the root of the element
        document.removeEventListener('click', this.onOutsideClick);
    },
    methods: {
        onOutsideClick() {
            ...
        }
    }
}

使用keep-alive保持组件活着

当使用keepalive时,vue会对你的组件产生影响,并使它在后台保持活动状态,这意味着只有1个实例存在.如果您有大量路由,这可能会消耗更多内存

<keep-alive>
    <router-view></router-view>
</keep-alive>