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kotlinlang

Is there a way to update *some properties* in a *JSON file* by parsing a `data class` that doesn't have all the properties of that *file* without *losing the properties* that are not part of the `data class` yet exist in the *JSON file*?

It's possible using `Json.parseToJsonElement` and manually update using `jsonObject?.toMutableMap()`

The only problem that it doesn't use the same Serial name in the data class and is not type-saftey.

can you just merge the keys back to the json object?
```val json = Json {
    ignoreUnknownKeys = true 
}
val input = json.parseToJsonElement(...)
val data1: Data = json.decodeFromJsonElement(input)
val data2 = data1.copy(...)
val output = JsonObject(input.jsonObject + json.encodeToJsonElement(data2).jsonObject)```

Thank you for the suggestion. It worked as expected and efficiently, a minor thing, for `parseToJsonElement` and `encodeToJsonElement`

You could also use `Json` directly instead of using the Json with ignore unknown keys.

A side note, for more advance use-cases where you want to update another `data class` inside your `data class` . You will have to choose to either use the one from `parseToJsonElement` or
You will have to deep merge the two JSON objects.

The only issue, if you remove something from the updated data class, you will still have it in the JSON element if it's there.