How to use the primeng/utils.FilterUtils.filter function in primeng

activateFilter() {
        let searchFields: string[] = this.filterBy.split(',');
        
        if (this.options && this.options.length) {
            if (this.group) {
                let filteredGroups = [];
                for (let optgroup of this.options) {
                    let filteredSubOptions = FilterUtils.filter(optgroup.items, searchFields, this.filterValue, this.filterMatchMode);
                    if (filteredSubOptions && filteredSubOptions.length) {
                        filteredGroups.push({
                            label: optgroup.label,
                            value: optgroup.value,
                            items: filteredSubOptions
                        });
                    }
                }

                this.optionsToDisplay = filteredGroups;
            }
            else {
                this.optionsToDisplay = FilterUtils.filter(this.options, searchFields, this.filterValue, this.filterMatchMode);
            }

            this.optionsChanged = true;

let filteredGroups = [];
                for (let optgroup of this.options) {
                    let filteredSubOptions = FilterUtils.filter(optgroup.items, searchFields, this.filterValue, this.filterMatchMode);
                    if (filteredSubOptions && filteredSubOptions.length) {
                        filteredGroups.push({
                            label: optgroup.label,
                            value: optgroup.value,
                            items: filteredSubOptions
                        });
                    }
                }

                this.optionsToDisplay = filteredGroups;
            }
            else {
                this.optionsToDisplay = FilterUtils.filter(this.options, searchFields, this.filterValue, this.filterMatchMode);
            }

            this.optionsChanged = true;
        }
    }