How to get all string from json document in jsoniq or javascript?

I am trying to get all the values of json string as a single string. for example in xquery xml

let $x := <a> welcome to the world of <b> JSONiq </b></a>
return string($x)

will return welcome to the world of JSONiq

what is the equvalent result of of following documents in JSONiq:

let $y := {"a":"welcome to the world of ","b":" JSONiq"}
return xxxx($y)

The result should be same welcome to the world of JSONiq If you know in javascript also it would be great.

Solution

First you need to get all values, either with libjn:values or its definition, then you can use fn:string-join to get a single string:

So

declare namespace libjn = "http://jsoniq.org/function-library";
let $y := {"a":"welcome to the world of ","b":" JSONiq"}
return string-join(libjn:values($y) ! string(), "")

or

let $y := {"a":"welcome to the world of ","b":" JSONiq"}
return string-join($y() ! string($y(.)), "")

This might also return "JSONiqwelcome to the world of ", since the object keys are unordered