I want to decode a JSON object that looks like this: { "boxes" : { "1" : { "items" : { "1" : "pencil", "2" : "ball" }, }, "2" : { "items" : { "1" : "teapot", "2" : "spoon", "3" : "towel" } } } } I have no contro…

There are a couple different ways to model this data structure. When the keys of an object are dynamic, often you’ll want to model this in Elm with a Dict. However, it looks like they’re really just incrementing with each value so many these are better handled as a List. That’s up to you! If you go…

Thank you, stephenreddek, for your clear answer. I try to make it work using Json.Decode.keyValuePairs, but that raises a question: are you sure about the pipeline with Json.Decode.map ((key, value) -> value)? Elm doesn’t accept it: The argument is: Decoder (List ( String, String )) But (|>) …

Oh I’m sorry! You’re absolutely right. I missed the List.map inside the Decoder.map. I’ll update that in my answer. It’ll just be Json.Decode.keyValuePairs (Json.Decode.String) |> Json.Decode.map (List.map (\(key, value) -> value))

The other solution works (I think) but it does simply ignore the information encoded in the numbers and assumes that the fields are always decoded in the right order. This will probably be the case but I think strictly speaking the fields in an object are unordered (so the sender or JavaScript or El…

Thanks for this solution too. For now I don’t need the order, but I will keep this in mind for future development.

JSON decode unknown number of fields

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iwtilma September 17, 2020, 9:03pm 6

Thank you very much. It works like a charm!
Still learning a lot.

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JSON decode unknown number of fields

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