Question 250444 in Flutter Question posted in
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Flutter – How to make all variables not required in json serializable

In json_serialization when i use the annotation @JsonKey(required: false), i am able to make a variable nullable, but then i have to annote all variables with this, it there a way to make this this general for a class, so all the variables can be nullable?

example

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is there a way to generalize this?

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2

Answers


  1. 0

    I think what you want is the includeIfNull property of the @JsonSerializable annotation:

    @JsonSerializable(includeIfNull: true)
class MyClass {
...
}

    This makes all fields nullable by default and includes fields with null values in the serialized output.

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  2. 0

    I see some issues here.
    Never heard about that json_serialization package, and couldn’t find it in pub.dev.
    You can create Dart objects based on data read from a JSON, but you can’t have NULL properties.

    All properties of a Dart class should be immediately initialized or have a late reference when you give them a value when the initState() is called.

    And a kind reminder that JSON doesn’t require a fixed data format, however, you can force it to always have the required properties, if you control both services that create and read JSON.

    If you use a third-party API or service, you must ensure that the properties exist before using them, and instead of storing every property on a Dart class, you can use a Map<String, Dynamic> to store the JSON content.

    If you really need to have a Dart class to store the values, you should initialize all the String parameters as empty, instead of NULL.

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