Uncaught (in promise) TypeError: Failed to set an indexed property on 'CSSStyleDeclaration': Indexed property setter is not supported.

原因分析：因使用了<el-table :cell-style="tableStyle"/>，methods返回字符串样式导致的报错
解决办法：将tableStyle逻辑中返回的字符串修改为对象

tableStyle({row, column, rowIndex, columnIndex}) {
    //return 'background:#009688; color:#fff!important;';
    return { 'background':'#009688', 'color':'#fff!important' };
},

Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'row')

原因分析：因在<el-table><el-table-column>中使用<template slot-scope="scope">导致的报错
解决办法：将<template slot-scope="scope">替换为<template #default="scope">

<el-table
    :data="tableData">
    <el-table-column>
        <template slot-scope="scope"> //不要了 
        <template #default="scope"> //替换为
        ...

runtime-core.esm-bundler.js:38 [Vue warn]: Invalid prop: validation failed. Expected one of ["", "default", "small", "large"], got value "mini".

原因分析：在<el-button/>、<el-form/>、<el-table/>、<el-input/>等组件中使用了size="mini"或者不在["", "default", "small", "large"]范围内属性。
解决办法：直接按需替换，例如：

<el-button
    size="mini"  //删除
    size="small" //替换为
    ...
 <el-table
    size="mini" //删除
    size="small" //替换为
    ...

destroyed()或beforeDestroy ()无效

解决办法：destroyed() 替换为unmounted ()，beforeDestroy()替换为beforeUnmount