How to control the icon direction when click outside (empty space)?
-fa-angle-up when the user open the dropdown

-fa-angle-down when the user close/default the dropdown

here is stackblitz

CodePudding user response：

In template you could use blur listener, so when focus goes away from element (e.g clicking outside) it would turn the flag.

(blur)="menuExpandCategory = !menuExpandCategory"

Forked: https://stackblitz.com/edit/angular-v6heew?file=src/app/app.component.html