In my experience, doing this on the HTML template proved difficult so I decided to use an event to call a function on TS and then check the condition. If true make condition equals to true and then use that variable on the ngIf on HTML
emptyClause(array:any) {
if (array.length === 0) {
// array empty or does not exist
this.emptyMessage=false;
}else{
this.emptyMessage=true;
}
}
HTML
<div class="row">
<form>
<div class="col-md-1 col-sm-1 col-xs-1"></div>
<div class="col-md-10 col-sm-10 col-xs-10">
<div [hidden]="emptyMessage" class="alert alert-danger">
No Clauses Have Been Identified For the Search Criteria
</div>
</div>
<div class="col-md-1 col-sm-1 col-xs-1"></div>
</form>