html
<div id="app"  @click="num === 0 ? num++ : num = 5">
    <transition-group name="list">
        <item v-for="n in num" :key=n />
    </transition-group>
</div>

CSS.list-enter {    opacity: 0;    transfORM: translateY(100%);
}.list-enter-active {    transition: .3s;
}.list-enter-to {    opacity: 1;    transform: translateY(0);
}

css.list-enter-active:nth-child(5n+2) {    transition-delay: .3s;
}.list-enter-active:nth-child(5n+3) {    transition-delay: .5s;
}.list-enter-active:nth-child(5n+4) {    transition-delay: .7s;
}.list-enter-active:nth-child(5n+5) {    transition-delay: .9s;
}复制代码

html<div id="app"  @click="num === 0 ? num++ : num = 5">
    <!-- 这里加上 v-bind:css="false" 让vue跳过对css的检测，让我们更好控制 动画完成的时机 -->
    <transition-group 
        v-bind:css="false"
        v-on:before-enter="beforeEnter" 
        v-on:enter="enter"
        v-on:after-enter="afterEnter">

        <item v-for="(n,index) in num" :key=n :data-delay=index*100 />

    </transition-group></div>复制代码

new Vue({    el: "#app",    data: () => ({        num: 0
    }),    methods: {        //让我们在 beforeEnter enter afterEnter 钩子里，把 vue 帮我们做的事，自己做一遍:
        //添加移除 class 类名，监听 transitionend 事件。
        beforeEnter(dom) {
            dom.classList.add('list-enter', 'list-enter-active');
        },        enter(dom,done) {            let delay = dom.dataset.delay;            setTimeout(function () {
                dom.classList.remove('list-enter');
                dom.classList.add('list-enter-to');                //监听 transitionend 事件
                var transitionend = window.ontransitionend ? "transitionend" : "WEBkitTransitionEnd";
                dom.addEventListener(transitionend, function onEnd() {
                  dom.removeEventListener(transitionend, onEnd);                  done(); //调用done() 告诉vue动画已完成，以触发 afterEnter 钩子
                });
            }, delay)
        },        afterEnter(dom) {
            dom.classList.remove('list-enter-to', 'list-enter-active');
        }
    }
})复制代码

html
<div id="app" @click="num ? num++ : num=5">
        <transition-group 
            v-bind:css="false" 
            v-on:before-enter="beforeEnter" 
            v-on:enter="enter"
            v-on:after-enter="afterEnter">

            <item v-for="(n,index) in num" 
                :key=n 
                :data-delay=index*100 
                data-y="100%"
                />

        </transition-group>
    </div>

new Vue({
    el: "#app",
    data: () => ({
        num: 0
    }),
    methods: {        beforeEnter(dom) {
            let { x = 0, y = 0, s = 1, opacity = 0 } = dom.dataset;
            dom.style.cssText = `transition: .3s;opacity: ${opacity};transform: scale(${s}) translateX(${x}) translateY(${y});`;
        },        enter(dom,done) {
            let delay = dom.dataset.delay;            setTimeout(function () {
                dom.style.cssText = `transition: .3s;opacity: 1;transform: scale(1) translateX(0) translateY(0);`;                //监听 transitionend 事件
                var transitionend = window.ontransitionend ? "transitionend" : "webkitTransitionEnd";
                dom.addEventListener(transitionend, function onEnd() {
                  dom.removeEventListener(transitionend, onEnd);                  done(); //调用done() 告诉vue动画已完成，以触发 afterEnter 钩子
                });
            }, delay)
        },        afterEnter(dom) {
            dom.style.cssText = "";
        }
    }
})

html
    <item v-for="(n,index) in num" 
        :key=n 
        :data-delay=index*100 
        :data-x="index%2 === 0 ? '-50%' : '50%'" 
        :data-y="getRandom()+'%'"
        :data-s="Math.random()"
    />

getRandom() {    var rate = Math.floor(Math.random() * 90 + 10);    return Math.random() > 0.5 ? rate : -1 * rate;
}