Element: [Bug Report] el-table can't show-summary with height when async data

[zsedcbm]

Element UI version

2.12.0

OS/Browsers version

win10 / chrome 77

Vue version

2.6.10

Reproduction Link

https://codepen.io/zsedcbm/pen/VwwmvRx

Steps to reproduce

3 cases

first:

1. table with height and show-summary and set empty array in start
2. Set a new array of values to the table
3. summary not show

second:

1. table with height and show-summary and set not empty array in start
2. Set a new array of values to the table
3. summary show success

third:

1. table show-summary and without height and set empty array in start
2. Set a new array of values to the table
3. summary show success

What is Expected?

1. table show-summary and without height and set empty array in start
2. Set a new array of values to the table
3. summary show success

What is actually happening?

el-table can't show-summary with height when async data

[zsedcbm]

1. 当 el-table 设置了height和show-summary时, 初始化的时候如果是空的数组, 后面设置新的数组, 表尾不会显示
2. 当 el-table 设置了height和show-summary时, 初始化的时候如果不是空的数组, 后面设置新的数组, 表尾会显示
3. 当 el-table 设置了show-summary 但是没有设置height时, 初始化的时候如果是空的数组, 后面设置新的数组, 表尾会显示

[suochencheng]

tableData: [
{

             }
         ],

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.