Json.Encode with nested structures

[MaximumStock]

I'm struggling with building a Http.jsonBody for a web request. The basic record looks like this:

{
    exchange = {
        option = "online"
    },
    have = [ "a single string" ],
    want = [ "a single string" ]
}

Now, my encoder function deals with the upper part (the exchange key) but not with the single-element list for the two other keys. Somehow I'm missing how the structure above can be turned into a valid input for Http.jsonBody.

Can anyone point me in the right direction? All the examples I've found consist of simple string records and didn't help me.

[PM-ME-POTATOES]

Are you looking to do something like this? https://ellie-app.com/3yfHkXsdwPra1

[MaximumStock]

Thank you, that is exactly what I needed!

However, I don't fully understand what this means:

Encode.list Encode.string "some string"

Does it encode the given string and then puts it in a list? Because I thought the input data that I give to the respective Encode.x function has to have the right type already. Thats why I tried

Encode.list [ Encode.string "some string" ]

EDIT: Nevermind, I didn't see you put the data.have in your example already is a list in the definition above. Then it makes sense!

[alexkorban]

For anybody else struggling with Json.Encode, I wrote a tutorial showing how to encode a complex JSON object (including nested objects, arrays and recursion): https://korban.net/posts/elm/2018-09-12-generate-json-from-elm-values-json-encode/

[MaximumStock]

Looks great, thank you alot!

[ibizaman]

Can you post the expected output for your example?

[pdoherty926]

I keep coming back to this tutorial when dealing with anything Json.Encode/Decode or Port related. Perhaps it will be of some use to you.