I am getting a lot of errors of: TypeError: Object doesn't support property or method 'forEach'

Although I don't seem to find exactly the source, nor reproduce it, it does looks as if it originates from within the implementation of mdb-auto-completer, perhaps with option list is empty

Here is a snippet of production code: n.prototype.show=function(){this._isOpen=!0},n.prototype.hide=function(){this._isOpen=!1},n.prototype.removeHighlight=function(n){var e=this;setTimeout(function(){e.optionList.forEach(function(t,l){var i=t.nativeElement.querySelectorAll(".completer-row");l===n?e.renderer.addClass(t.nativeElement.firstElementChild,"highlight-row"):l!==n&&i.forEach(function(n){e.renderer.removeClass(n,"highlight-row")})})},0)},n.prototype.highlightRow=function(n){var e=this;this._allItems=this.optionList.filter(function(n){return n.nativeElement.firstElementChild.classList.contains("completer-row")}).map(function(n){return n.nativeElement}),this._allItems[n]&&this.optionList.forEach(function(t,l){var i=t.nativeElement.querySelectorAll(".completer-row");n===l&&(e.removeHighlight(n),e.renderer.addClass(i[i.length-1],"highlight-row"))}),this._selectedItemIndex=n}

The source is the foreach in here: ... (t.nativeElement.firstElementChild,"highlight-row"):l!==n&&i.forEach(function(n){e.renderer.removeClass(n,"highlight-row")})})},0)},n.protot ...

Are you familiar with this and can guide me to a solution ?