Async execution in vapor. How to control the cycle for in - swift

Question

func loadBy(_ req: Request) throws -> Future<[News]> {
let parentId = try req.parameters.next(String.self)
let parent = try self.findParentBy(req, parentId: parentId)
var childNews: [News] = []
let qq = parent.map(to: [News].self) { parentNews in
for chilId in parentNews!.childIds {
let ch = News.query(on: req).filter(\News.newsId == chilId).first().map(to: News?.self) { child in
if let child = child {
childNews.append(child)
}
return child
}
}
return childNews
}
return qq.flatMap(to: [News].self) { childNews in
return childNews.map { news in
Future.map(on: req) { news }
}.flatten(on: req)
}
}
returned before the values will be obtained
I would like to wait until the desired values are obtained and then return them

Answer 1

Thanks. It's works with
func loadBy(_ req: Request) throws -> Future<[News]> {
let parentId = try req.parameters.next(String.self)
let parent = try self.findParentBy(req, parentId: parentId)
var childNews: [News] = []
return parent.flatMap(to: [News].self) { parentNews in
return parentNews!.childIds.map { (key) in
return News.query(on: req).filter(\News.newsId == key).first().map(to: Void.self) { child in
if let child = child {
childNews.append(child)
}
}
}.flatten(on: req).map {
return childNews
}
}
}
func loadBy(_ req: Request) throws -> Future<[News]> {
let parentId = try req.parameters.next(String.self)
let parent = try self.findParentBy(req, parentId: parentId)
return parent.flatMap(to: [News].self) { parentNews in
return News.query(on: req).filter(\News.newsId ~~ parentNews!.childIds).all()
}
}