How to toggle Angular material expansion panel programmatically

Question

I just started working on an Angular 4 project with material design.

I am currently working with the expansion component, the API states that a disabled expansion pa

Answer 1

Simple implementation for array of panels

    ...
    Toggle
    ...

And in code

indexExpanded: number = -1;

togglePanels(index: number) {
    this.indexExpanded = index == this.indexExpanded ? -1 : index;
}