How to add a collapse icon in ngx-bootstrap Accordion

Question

In my Angular app that is using ngx-bootstrap, I would like to add a collapse icon which reflects the status of the accordion (collapsed/expanded) like the following:

Answer 1

You can basically do this in css :

.accordion-toggle[aria-expanded="true"]:before {
    content: "\f107";
    font: normal normal normal 14px/1 FontAwesome;
}

.accordion-toggle[aria-expanded="false"]:before {
    content: '\f106';
    font: normal normal normal 14px/1 FontAwesome;
}

Just have to style the before selector with the font familly of your favorite icon...