Vue 元素动画缓入效果

 效果展示

vue文件的指令使用

指令文件

//domSlowness.js

import Vue from 'vue';
 
// 判断元素是不是在视口之下
function isBelowViewport(el) {
    const rect = el.getBoundingClientRect();
    return rect.top > window.innerHeight;
}
const DISTANCE = 150;
const DURATION = 1000;
const animationMap = new WeakMap();

const ob = new IntersectionObserver(entries => {
    for (const entry of entries) {
        if (entry.isIntersecting) {    // 判断元素是否与视口交叉
            const animation = animationMap.get(entry.target);
            animation.play();
            ob.unobserve(entry.target);
        }
    }
})
Vue.directive('domSlown',{ 
    inserted(el,binding){
       
        if (!isBelowViewport(el)) {
            return;
        }
        const animation = el.animate([
            {
                transform: `translateY(${DISTANCE}px)`,
                opacity: 0.5
            },
            {
                transform: 'translateY(0)',
                opacity: 1
            },
        ],
            {
                duration: DURATION,
                easing: 'ease'
            })
        animation.pause();
        animationMap.set(el, animation);
        ob.observe(el);
    },
    unbind(el) {
        ob.unobserve(el);
    }
})
 
 

主文件入口引用指令文件

//main.js
import '@/assets/domSlowness.js'