Problem on displaying collapse/expand icon using *ngFor in mat-expansion-panel on angular

Question

I have a customized icon for collapse and expand. As I have a nested array, It will trigger all header. It should be click first header that only expand in 1 st header. It should not trigger all header. How to separate control it ? Here is stackblitz

Answer 1

You need to create a boolan for evry posts open/close