el-dialog实现弹窗拖拽+水平方向伸缩

import Vue from 'vue';
// v-dialogDrag: 弹窗拖拽属性
/*
 *  使用方法
 *  将以下代码复制到一个dialogDrag.js文件中，然后在入口文件main.js中导入：import './utils/dialogDrag.js'；
 *  给elementUI的dialog上加上 v-dialogDrag 指令就可以实现弹窗的全屏和拉伸了。
 *  给dialog设置 :close-on-click-modal="false" , 禁止点击遮罩层关闭弹出层
 *  如果是form表单，不要将提交等按钮放置el-form-item，以免在上下拉伸时被隐藏
 */
// v-dialogDrag: 弹窗拖拽+水平方向伸缩
Vue.directive('dialogDrag', {
    bind(el, binding, vnode, oldVnode) {
        // 弹框可拉伸最小宽高
        const minWidth = 400;
        const minHeight = 300;
        // 初始非全屏
        let isFullScreen = false;
        // 当前顶部高度
        let nowMarginTop = 0;
        // 获取弹框头部（这部分可双击全屏）
        const dialogHeaderEl = el.querySelector('.el-dialog__header');
        // 弹窗
        const dragDom = el.querySelector('.el-dialog');
        // 给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；
        dragDom.style.overflow = 'auto';
        // 清除选择头部文字效果
        // dialogHeaderEl.onselectstart = new Function("return false");
        // 头部加上可拖动cursor
        dialogHeaderEl.style.cursor = 'move';
        // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
        // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
        const sty = (() => {
            if (window.document.currentStyle) {
                return (dom, attr) => dom.currentStyle[attr];
            } else {
                return (dom, attr) => getComputedStyle(dom, false)[attr];
            }
        })();
        const moveDown = (e) => {
            // 鼠标按下，计算当前元素距离可视区的距离
            const disX = e.clientX - dialogHeaderEl.offsetLeft;
            const disY = e.clientY - dialogHeaderEl.offsetTop;

            const screenWidth = document.body.clientWidth; // body当前宽度
            const screenHeight = document.documentElement.clientHeight; // 可见区域高度(应为body高度，可某些环境下无法获取)

            const dragDomWidth = dragDom.offsetWidth; // 对话框宽度
            const dragDomheight = dragDom.offsetHeight; // 对话框高度

            const minDragDomLeft = dragDom.offsetLeft;
            const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth;

            const minDragDomTop = dragDom.offsetTop;
            const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomheight;

            // 获取到的值带px 正则匹配替换
            let styL = sty(dragDom, 'left');
            let styT = sty(dragDom, 'top');

            // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
            if (styL.includes('%')) {
                styL = +document.body.clientWidth * (+styL.replace(/\%/g, '') / 100);
                styT = +document.body.clientHeight * (+styT.replace(/\%/g, '') / 100);
            } else {
                styL = +styL.replace(/\px/g, '');
                styT = +styT.replace(/\px/g, '');
            }

            document.onmousemove = function (e) {
                // 通过事件委托，计算移动的距离
                let left = e.clientX - disX;
                let top = e.clientY - disY;

                // 边界处理
                if (-left > minDragDomLeft) {
                    left = -minDragDomLeft;
                } else if (left > maxDragDomLeft) {
                    left = maxDragDomLeft;
                }

                if (-top > minDragDomTop) {
                    top = -minDragDomTop;
                } else if (top > maxDragDomTop) {
                    top = maxDragDomTop;
                }

                // 移动当前元素
                dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`;
            };

            document.onmouseup = function (e) {
                document.onmousemove = null;
                document.onmouseup = null;
            };
        };
        dialogHeaderEl.onmousedown = moveDown;
        // 当前宽高
        let nowWidth = 0;
        // let nowHight = 0
        // 双击头部全屏效果
        dialogHeaderEl.ondblclick = (e) => {
            if (isFullScreen === false) {
                // nowHight = dragDom.clientHeight
                nowWidth = dragDom.clientWidth;
                nowMarginTop = dragDom.style.marginTop;
                dragDom.style.left = 0;
                dragDom.style.top = 0;
                dragDom.style.height = '100VH';
                dragDom.style.width = '100VW';
                dragDom.style.marginTop = 0;
                isFullScreen = true;
                dialogHeaderEl.style.cursor = 'initial';
                dialogHeaderEl.onmousedown = null;
            } else {
                dragDom.style.height = 'auto';
                dragDom.style.width = nowWidth + 'px';
                dragDom.style.marginTop = nowMarginTop;
                isFullScreen = false;
                dialogHeaderEl.style.cursor = 'move';
                dialogHeaderEl.onmousedown = moveDown;
            }
        };
        dragDom.onmousemove = function (e) {
            // let moveE = e
            if (e.clientX > dragDom.offsetLeft + dragDom.clientWidth - 10 || dragDom.offsetLeft + 10 > e.clientX) {
                dragDom.style.cursor = 'w-resize';
            } else if (el.scrollTop + e.clientY > dragDom.offsetTop + dragDom.clientHeight - 10) {
                dragDom.style.cursor = 's-resize';
            } else {
                dragDom.style.cursor = 'default';

                dragDom.onmousedown = null;
            }
            dragDom.onmousedown = (e) => {
                const clientX = e.clientX;
                const clientY = e.clientY;
                const elW = dragDom.clientWidth;
                const elH = dragDom.clientHeight;
                const EloffsetLeft = dragDom.offsetLeft;
                const EloffsetTop = dragDom.offsetTop;
                dragDom.style.userSelect = 'none';
                const ELscrollTop = el.scrollTop;
                // 判断点击的位置是不是为头部
                if (clientX > EloffsetLeft && clientX < EloffsetLeft + elW && clientY > EloffsetTop && clientY < EloffsetTop + 100) {
                    // 如果是头部在此就不做任何动作，以上有绑定dialogHeaderEl.onmousedown = moveDown;
                } else {
                    document.onmousemove = function (e) {
                        // 移动时禁用默认事件
                        e.preventDefault();
                        // 左侧鼠标拖拽位置
                        if (clientX > EloffsetLeft && clientX < EloffsetLeft + 10) {
                            // 往左拖拽
                            if (clientX > e.clientX) {
                                dragDom.style.width = elW + (clientX - e.clientX) * 2 + 'px';
                            }
                            // 往右拖拽
                            if (clientX < e.clientX) {
                                if (dragDom.clientWidth < minWidth) {
                                    console.log();
                                } else {
                                    dragDom.style.width = elW - (e.clientX - clientX) * 2 + 'px';
                                }
                            }
                        }
                        // 右侧鼠标拖拽位置
                        if (clientX > EloffsetLeft + elW - 10 && clientX < EloffsetLeft + elW) {
                            // 往左拖拽
                            if (clientX > e.clientX) {
                                if (dragDom.clientWidth < minWidth) {
                                    console.log();
                                } else {
                                    dragDom.style.width = elW - (clientX - e.clientX) * 2 + 'px';
                                }
                            }
                            // 往右拖拽
                            if (clientX < e.clientX) {
                                dragDom.style.width = elW + (e.clientX - clientX) * 2 + 'px';
                            }
                        }
                        // 底部鼠标拖拽位置
                        if (ELscrollTop + clientY > EloffsetTop + elH - 20 && ELscrollTop + clientY < EloffsetTop + elH) {
                            // 往上拖拽
                            if (clientY > e.clientY) {
                                if (dragDom.clientHeight < minHeight) {
                                    console.log();
                                } else {
                                    dragDom.style.height = elH - (clientY - e.clientY) * 2 + 'px';
                                }
                            }
                            // 往下拖拽
                            if (clientY < e.clientY) {
                                dragDom.style.height = elH + (e.clientY - clientY) * 2 + 'px';
                            }
                        }
                    };
                    // 拉伸结束
                    document.onmouseup = function (e) {
                        document.onmousemove = null;

                        document.onmouseup = null;
                    };
                }
            };
        };
    }
});