Angular Material 6.0.1 Tree default opened and expand/collapse all

Question

I\'m using the Angular Material Tree in my project. Is it possible to have the tree opened by default.

And could there be a way to expand/collapse all the nodes at once

Answer 1

In addition make sure that treeControl nodes are set. After loading data you should

treeControl.dataNodes = nodes; 
treeControl.expandAll()

See this github issue