How to expand all level 2 titles in sidebar including inactive pages？如何展开侧边栏的所有标题？

[imageslr]

Feature request

Add a configuration item like collapsable to support expanding all level 2 titles in sidebar including which of inactive pages.

添加一个类似collapsable的配置项，以默认在侧边栏显示所有标题。

What problem does this feature solve?

Currently the sidebar will only show level 2 titles in current active page. I want to display all level 2 titles even it's an unfocus page. Like this:

目前侧边栏只会显示当前页面的二级标题，我希望展开所有页面的二级标题，就像这样：

What does the proposed API look like?

sidebar: {
 //...
},
expandAllGroup: true

How should this be implemented in your opinion?

When server generates sidebar arrays, add all level 2 titles in that array instead of only adding that of current active page.

在生成侧边栏的时候，把所有页面的二级标题都显示出来，而不是只显示当前页面的二级标题。

Maybe modify following codes in line 4:

<SidebarGroup v-if="item.type === 'group'"
    :item="item"
    :first="i === 0"
    :open="i === openGroupIndex" // change to → :open="expandAllGroup || i === openGroupIndex"
    :collapsable="item.collapsable"
    @toggle="toggleGroup(i)"
/>

Are you willing to work on this yourself?

I never contribute to a big project before. It couldn't be better if I can do it.

[ulivz]

PR welcome!

[imageslr]

Great! I will work on this after a few days😄.

[imageslr]

I have finished this feat yesterday. Thanks for reviewing my pr @ulivz .