How to use the element-ui/src/utils/dom.getStyle function in element-ui

table.$emit("cell-mouse-enter", hoverState.row, hoverState.column, hoverState.cell, event);
      }

      // 判断是否text-overflow, 如果是就显示tooltip
      const cellChild = event.target.querySelector(".cell");
      // if (!(hasClass(cellChild, "el-tooltip") && cellChild.childNodes.length)) {
      //   return;
      // }
      // use range width instead of scrollWidth to determine whether the text is overflowing
      // to address a potential FireFox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1074543#c3
      const range = document.createRange();
      range.setStart(cellChild, 0);
      range.setEnd(cellChild, cellChild.childNodes.length);
      const rangeWidth = range.getBoundingClientRect().width;
      const padding =
        (parseInt(getStyle(cellChild, "paddingLeft"), 10) || 0) +
        (parseInt(getStyle(cellChild, "paddingRight"), 10) || 0);
      // if (
      //   (rangeWidth + padding > cellChild.offsetWidth || cellChild.scrollWidth > cellChild.offsetWidth) &&
      //   this.$refs.tooltip
      // ) {
      //   const tooltip = this.$refs.tooltip;
      //   // TODO 会引起整个 Table 的重新渲染，需要优化
      //   this.tooltipContent = cell.innerText || cell.textContent;
      //   tooltip.referenceElm = cell;
      //   tooltip.$refs.popper && (tooltip.$refs.popper.style.display = "none");
      //   tooltip.doDestroy();
      //   tooltip.setExpectedState(true);
      //   this.activateTooltip(tooltip);
      // }
    },

const hoverState = table.hoverState = {cell, column, row};
        table.$emit('cell-mouse-enter', hoverState.row, hoverState.column, hoverState.cell, event);
      }

      // 判断是否text-overflow, 如果是就显示tooltip
      const cellChild = event.target.querySelector('.cell');
      if (!(hasClass(cellChild, 'el-tooltip') && cellChild.childNodes.length)) {
        return;
      }
      // use range width instead of scrollWidth to determine whether the text is overflowing
      // to address a potential FireFox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1074543#c3
      const range = document.createRange();
      range.setStart(cellChild, 0);
      range.setEnd(cellChild, cellChild.childNodes.length);
      const rangeWidth = range.getBoundingClientRect().width;
      const padding = (parseInt(getStyle(cellChild, 'paddingLeft'), 10) || 0) +
        (parseInt(getStyle(cellChild, 'paddingRight'), 10) || 0);
      if ((rangeWidth + padding > cellChild.offsetWidth || cellChild.scrollWidth > cellChild.offsetWidth) && this.$refs.tooltip) {
        const tooltip = this.$refs.tooltip;
        // TODO 会引起整个 Table 的重新渲染，需要优化
        this.tooltipContent = cell.innerText || cell.textContent;
        tooltip.referenceElm = cell;
        tooltip.$refs.popper && (tooltip.$refs.popper.style.display = 'none');
        tooltip.doDestroy();
        tooltip.setExpectedState(true);
        this.activateTooltip(tooltip);
      }
    },

table.$emit('cell-mouse-enter', hoverState.row, hoverState.column, hoverState.cell, event);
      }

      // 判断是否text-overflow, 如果是就显示tooltip
      const cellChild = event.target.querySelector('.cell');
      if (!(hasClass(cellChild, 'el-tooltip') && cellChild.childNodes.length)) {
        return;
      }
      // use range width instead of scrollWidth to determine whether the text is overflowing
      // to address a potential FireFox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1074543#c3
      const range = document.createRange();
      range.setStart(cellChild, 0);
      range.setEnd(cellChild, cellChild.childNodes.length);
      const rangeWidth = range.getBoundingClientRect().width;
      const padding = (parseInt(getStyle(cellChild, 'paddingLeft'), 10) || 0) +
        (parseInt(getStyle(cellChild, 'paddingRight'), 10) || 0);
      if ((rangeWidth + padding > cellChild.offsetWidth || cellChild.scrollWidth > cellChild.offsetWidth) && this.$refs.tooltip) {
        const tooltip = this.$refs.tooltip;
        // TODO 会引起整个 Table 的重新渲染，需要优化
        this.tooltipContent = cell.innerText || cell.textContent;
        tooltip.referenceElm = cell;
        tooltip.$refs.popper && (tooltip.$refs.popper.style.display = 'none');
        tooltip.doDestroy();
        tooltip.setExpectedState(true);
        this.activateTooltip(tooltip);
      }
    },

)
      }

      // 判断是否text-overflow, 如果是就显示tooltip
      const cellChild = event.target.querySelector('.cell')
      if (!(hasClass(cellChild, 'el-tooltip') && cellChild.childNodes.length)) {
        return
      }
      // use range width instead of scrollWidth to determine whether the text is overflowing
      // to address a potential FireFox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1074543#c3
      const range = document.createRange()
      range.setStart(cellChild, 0)
      range.setEnd(cellChild, cellChild.childNodes.length)
      const rangeWidth = range.getBoundingClientRect().width
      const padding =
        (parseInt(getStyle(cellChild, 'paddingLeft'), 10) || 0) +
        (parseInt(getStyle(cellChild, 'paddingRight'), 10) || 0)
      if (
        (rangeWidth + padding > cellChild.offsetWidth ||
          cellChild.scrollWidth > cellChild.offsetWidth) &&
        this.$refs.tooltip
      ) {
        const tooltip = this.$refs.tooltip
        // TODO 会引起整个 Table 的重新渲染，需要优化
        this.tooltipContent = cell.innerText || cell.textContent
        tooltip.referenceElm = cell
        tooltip.$refs.popper && (tooltip.$refs.popper.style.display = 'none')
        tooltip.doDestroy()
        tooltip.setExpectedState(true)
        this.activateTooltip(tooltip)
      }
    },

const insertDom = (parent, el, binding) => {
    if (!el.domVisible && getStyle(el, 'display') !== 'none' && getStyle(el, 'visibility') !== 'hidden') {
      Object.keys(el.maskStyle).forEach(property => {
        el.mask.style[property] = el.maskStyle[property];
      });

      if (el.originalPosition !== 'absolute' && el.originalPosition !== 'fixed') {
        addClass(parent, 'el-loading-parent--relative');
      }
      if (binding.modifiers.fullscreen && binding.modifiers.lock) {
        addClass(parent, 'el-loading-parent--hidden');
      }
      el.domVisible = true;

      parent.appendChild(el.mask);
      Vue.nextTick(() => {
        if (el.instance.hiding) {
          el.instance.$emit('after-leave');

Vue.nextTick(() => {
        if (binding.modifiers.fullscreen) {
          el.originalPosition = getStyle(document.body, 'position');
          el.originalOverflow = getStyle(document.body, 'overflow');
          el.maskStyle.zIndex = PopupManager.nextZIndex();

          addClass(el.mask, 'is-fullscreen');
          insertDom(document.body, el, binding);
        } else {
          removeClass(el.mask, 'is-fullscreen');

          if (binding.modifiers.body) {
            el.originalPosition = getStyle(document.body, 'position');

            ['top', 'left'].forEach(property => {
              const scroll = property === 'top' ? 'scrollTop' : 'scrollLeft';
              el.maskStyle[property] = el.getBoundingClientRect()[property] +
                document.body[scroll] +
                document.documentElement[scroll] -
                parseInt(getStyle(document.body, `margin-${ property }`), 10) +

instance.originalOverflow = getStyle(document.body, 'overflow');
    maskStyle.zIndex = PopupManager.nextZIndex();
  } else if (options.body) {
    instance.originalPosition = getStyle(document.body, 'position');
    ['top', 'left'].forEach(property => {
      let scroll = property === 'top' ? 'scrollTop' : 'scrollLeft';
      maskStyle[property] = options.target.getBoundingClientRect()[property] +
        document.body[scroll] +
        document.documentElement[scroll] +
        'px';
    });
    ['height', 'width'].forEach(property => {
      maskStyle[property] = options.target.getBoundingClientRect()[property] + 'px';
    });
  } else {
    instance.originalPosition = getStyle(parent, 'position');
  }
  Object.keys(maskStyle).forEach(property => {
    instance.$el.style[property] = maskStyle[property];
  });
};

Vue.nextTick(() => {
        if (binding.modifiers.fullscreen) {
          el.originalPosition = getStyle(document.body, 'position');
          el.originalOverflow = getStyle(document.body, 'overflow');
          el.maskStyle.zIndex = PopupManager.nextZIndex();

          addClass(el.mask, 'is-fullscreen');
          insertDom(document.body, el, binding);
        } else {
          removeClass(el.mask, 'is-fullscreen');

          if (binding.modifiers.body) {
            el.originalPosition = getStyle(document.body, 'position');

            ['top', 'left'].forEach(property => {
              const scroll = property === 'top' ? 'scrollTop' : 'scrollLeft';
              el.maskStyle[property] = el.getBoundingClientRect()[property] +
                document.body[scroll] +
                document.documentElement[scroll] -
                parseInt(getStyle(document.body, `margin-${ property }`), 10) +
                'px';
            });
            ['height', 'width'].forEach(property => {
              el.maskStyle[property] = el.getBoundingClientRect()[property] + 'px';
            });

            insertDom(document.body, el, binding);
          } else {
            el.originalPosition = getStyle(el, 'position');

const addStyle = (options, parent, instance) => {
  let maskStyle = {};
  if (options.fullscreen) {
    instance.originalPosition = getStyle(document.body, 'position');
    instance.originalOverflow = getStyle(document.body, 'overflow');
    maskStyle.zIndex = PopupManager.nextZIndex();
  } else if (options.body) {
    instance.originalPosition = getStyle(document.body, 'position');
    ['top', 'left'].forEach(property => {
      let scroll = property === 'top' ? 'scrollTop' : 'scrollLeft';
      maskStyle[property] = options.target.getBoundingClientRect()[property] +
        document.body[scroll] +
        document.documentElement[scroll] +
        'px';
    });
    ['height', 'width'].forEach(property => {
      maskStyle[property] = options.target.getBoundingClientRect()[property] + 'px';
    });
  } else {
    instance.originalPosition = getStyle(parent, 'position');
  }