Parsing JSON to string key and values

Question

Is there a way to parse a JSON as a Map<String, String> instead of Map<String, dynamic> when using Dart's json.decode.

For example with JSON of:

{
 'a': 2,
 'b': 'c'
}

It would parse into:

{
 'a': '2',
 'b': 'c'
}

Answer 1

Sadly, no. The code for decoding a Map starts with a Map<String, dynamic> and adds values as they are read, so there is no way to make the value type more specific.

Look into these for other options:

• Create a new Map with the right type from any source map: https://api.dartlang.org/stable/2.1.0/dart-core/Map/Map.from.html – you pay a one-time cost for copying the values.
• Create a type-safe view over an existing Map - https://api.dartlang.org/stable/2.1.0/dart-core/Map/cast.html – no copy cost, but you pay the overhead of wrapping/casting on each access of the original Map