src/vs/platform/dnd/browser/dnd.ts/containsDragType
export function containsDragType(event: DragEvent, ...dragTypesToFind: string[]): boolean {
	if (!event.dataTransfer) {
		return false;
	}

	const dragTypes = event.dataTransfer.types;
	const lowercaseDragTypes: string[] = [];
	for (let i = 0; i < dragTypes.length; i++) {
		lowercaseDragTypes.push(dragTypes[i].toLowerCase()); // somehow the types are lowercase
	}

	for (const dragType of dragTypesToFind) {
		if (lowercaseDragTypes.indexOf(dragType.toLowerCase()) >= 0) {
			return true;
		}
	}

	return false;
}