message: escape special chars to use them in ng-option-highlight
diff: @@ -37,6 +37,10 @@ export class NgOptionHighlightDirective implements OnChanges, AfterViewInit {
  }
  }
  + private _escapeRegExp(str: string): string {
  + return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
  + }
  +
  private _highlightLabel() {
  const label = this.label;
  if (!this.term) {
  @@ -44,8 +48,8 @@ export class NgOptionHighlightDirective implements OnChanges, AfterViewInit {
  return;
  }
  - const alternationString = this.term.replace(' ', '|')
  - const termRegex = new RegExp(alternationString, 'gi')
  + const alternationString = this._escapeRegExp(this.term).replace(' ', '|');
  + const termRegex = new RegExp(alternationString, 'gi');
  this._setInnerHtml(label.replace(termRegex, `<span class=\"highlighted\">$&</span>`))
  }
  