Option to value with default value

Question

With the help of answer of this question I need help with the specific syntax on how to retrieve values from option types in the following case.

type Query = {
    q : string
    pageSize : int option
}

let search (query : Query) =
    let url = sprintf "foo.com?q=%spageSize=%i" query.q (query.pageSize |> 10 |< query.pageSize) // ???

Syntax help for (query.pageSize |> 10 |< query.pageSize)

Answer 1

Option.defaultValue is your friend:

type Query = {
  q : string
  pageSize : int option
}
let q = {q = "foo"; pageSize = None}
let p = q.pageSize |> Option.defaultValue 10

Answer 2

The answer you linked provides a pretty clear illustration of the syntax:

input |> defaultArg <| ""

In your case, the input is query.pageSize and the default value is 10 instead of empty string. So:

query.pageSize |> defaultArg <| 10