: {{item.value}}
    </el-dropdown-item>
</template>  command= {{item.value}}  how to write this? 
    : {{item.value}}
    </el-dropdown-item>
</template>  command= {{item.value}}  how to write this? 
 use "item.value" with Key or abbreviation: comment= "item.value" 
 suggest the landlord take a good look at the API of vuejs 
add @ command= "fn" fn to el-dropdown. The command of el-dropdown-item is the parameter of calling fn.
Next: The problem of automatic conversion of echarts stacked bar chart back to linetype chart stacking
like this [array [xxx], array [xxx], array [xxx].] merge all xxx in array into one array [xxx.] ...