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'
}

Kevin Moore · Accepted Answer · 2019-01-15 03:15:28Z

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

answered Jan 15, 2019 at 3:15

Kevin Moore

6,1932 gold badges32 silver badges44 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

lrn Over a year ago

Since parsing an unquoted 2 as a string would be a violation of the JSON specification, that's not something the JSON parse will do for you. It sounds like you need to convert the map. You can do:

var jsonMap = jsonDecode(...); Map<String, String> myMap = Map.fromEntries(jsonMap.entries.map((e) => MapEntry(e.key, "${e.value}")));

.

Collectives™ on Stack Overflow

Parsing JSON to string key and values

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related