How to change List<String> to List<dynamic> in Dart 2?

Question

I have a List<String> and I need to change it to List<dynamic> in Dart 2.

First, I tried this code but it doesn't work:

var str_list = ["aa", "bb"];

// fails - is not dynamic
// gives List<String> 
List<dynamic> target_list_0 = str_list;

Later, I tried these 2 ways:

// succeeds - is dynamic
// gives List<dynamic> 
var target_list_1 = [] + str_list;

// succeeds - is dynamic
// gives List<dynamic> 
var target_list_2 = List<dynamic>.from(str_list);

It works but I am not sure it is the best (or idiomatic) way to fix the problem. I would like to write my Dart-2 code as clean as possible, could you help?

Edit

@matanlurey asked clear example where this pattern is necessary and how I am using it.

I am developing something like twitter but more complex (not only #hashtags and @mentions but words that have internal structure). So, I make some modification of the source text, then split it by whitespace (or parentheses) to words and then examine word by word. If the word is special I change the string to a map (containing parsed info). The change is happening in-place in the list. And that is where I need it dynamic. I have this source code:

var split_regexp = new RegExp(r"[^\s\(\)]+|[\s\(\)]+");
var body_matches = split_regexp.allMatches(body_part);

var body = [] + body_matches.map(
    (m) => m.group(0)
).toList();

// ... processing it ...

Currently, I am rewriting it from javascript (to which I rewrote it from python). Both the languages are able to catch the text by which I split words, it is much easier:

// python
body = re.split(r"([\s\(\)]+)", body)

// javascript
body = body.split(/([\s\(\)]+)/g)

Is it possible to write it so simple in Dart? I think not - because I need the splitter whitespace (or splitter parentheses or anything in future versions of my app) and dart split doesn't catch it.

Answer 1

List.from(...) is going to be the most idiomatic way, today. In fact, the style guide now recommends it if you are trying to change the type of an existing list:

// If you want to change the type, then calling List.from() is useful:

var numbers = [1, 2.3, 4]; // List<num>.
numbers.removeAt(1); // Now it only contains integers.
var ints = new List<int>.from(numbers);

as clean as possible

Probably you don't want List<dynamic> at all, in that case. It might help if you can give clear examples where this pattern is necessary and how you are using it.