vue-element-admin/src/directive/sticky.js

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(function() {
const vueSticky = {};
let listenAction;
vueSticky.install = Vue => {
Vue.directive('sticky', {
inserted(el, binding) {
const params = binding.value || {},
stickyTop = params.stickyTop || 0,
zIndex = params.zIndex || 1000,
elStyle = el.style;
elStyle.position = '-webkit-sticky';
elStyle.position = 'sticky';
// if the browser support css stickyCurrently Safari, Firefox and Chrome Canary
// if (~elStyle.position.indexOf('sticky')) {
// elStyle.top = `${stickyTop}px`;
// elStyle.zIndex = zIndex;
// return
// }
const elHeight = el.getBoundingClientRect().height;
const elWidth = el.getBoundingClientRect().width;
elStyle.cssText = `top: ${stickyTop}px; z-index: ${zIndex}`;
const parentElm = el.parentNode || document.documentElement;
const placeholder = document.createElement('div');
placeholder.style.display = 'none';
placeholder.style.width = `${elWidth}px`;
placeholder.style.height = `${elHeight}px`;
parentElm.insertBefore(placeholder, el)
let active = false;
const getScroll = (target, top) => {
const prop = top ? 'pageYOffset' : 'pageXOffset';
const method = top ? 'scrollTop' : 'scrollLeft';
let ret = target[prop];
if (typeof ret !== 'number') {
ret = window.document.documentElement[method];
}
return ret;
};
const sticky = () => {
if (active) {
return
}
if (!elStyle.height) {
elStyle.height = `${el.offsetHeight}px`
}
elStyle.position = 'fixed';
elStyle.width = `${elWidth}px`;
placeholder.style.display = 'inline-block';
active = true
};
const reset = () => {
if (!active) {
return
}
elStyle.position = '';
placeholder.style.display = 'none';
active = false;
};
const check = () => {
const scrollTop = getScroll(window, true);
const offsetTop = el.getBoundingClientRect().top;
if (offsetTop < stickyTop) {
sticky();
} else {
if (scrollTop < elHeight + stickyTop) {
reset()
}
}
};
listenAction = () => {
check()
};
window.addEventListener('scroll', listenAction)
},
unbind() {
window.removeEventListener('scroll', listenAction)
}
})
};
if (typeof exports == 'object') {
module.exports = vueSticky
} else if (typeof define == 'function' && define.amd) {
define([], () => vueSticky)
} else if (window.Vue) {
window.vueSticky = vueSticky;
Vue.use(vueSticky)
}
}());