In Vue3, How can I invoke method exposed by child component before child component being mounted?

[tnmoon]

For example, I want to call expand method as soon as a tree component is created. if I use template ref, it will be undefined when I try to access the child component in setup function. if I use onMounted function, the tree component will first be unexpanded when show up, and expanded after a flash.

So, is there any way to call exposed method after child component being created, but before mounted?

[ChuTingzj]

I think you should use the state of the tree component itself to control whether it expands or not, rather than calling the exposed methods of the tree component externally, which is more in line with Vue's design philosophy

[LinusBorg]

There's no real way to do this, as the mounting process is synchronous.

Why would you need to call a method instead of passing expand: true as a prop?