Builtin façade methods

ts2dart supports automatically translating "façade" methods, i.e. translating certain methods of well known types from JavaScript/TypeScript into their Dart equivalents. This mode is configurable and enabled using the option translateBuiltins.

Support is experimental - expect bugs.

You can find the supported, builtin façade methods in facade_converter.ts.

Currently supported:

• Array.push ==> List.add
• Array.map ==> List.map(...).toList()
• Array.concat ==> new List.from(...)..addAll(...)
• Array.isArray ==> ... is List
• Map.get(k) ==> m[k]
• Map.set(k, v) ==> m[k] = v;
• Map.has(k) ==> m.contains(k)
• /regexp/ ==> new RegExp(\r'regexp')
• RegExp.test ==> RegExp.hasMatch
• RegExp.exec ==> RegExp.allMatches(...).toList()
• CONST_EXPR, forwardRef as we had before, but with more precision.

Meaning you should be able to just write:

var xs: string[] = [];
xs.push('12');
var sum = 0;
xs.map((x) => parseInt(x)).forEach((x) => sum += x);

And for Maps:

var m = new Map<string, number>();
m.set('answer', 42);
console.log(m.get('answer'));

Fixing Untyped property access errors

To handle builtins, ts2dart has to know which calls to e.g. get are on Map, and which are on some unrelated object and should not be translated. If your code contains a get call on an unknown type (any in TypeScript), ts2dart will give an error like this:

[16:39:36] TS2DartError: [TSToDartTranspiler]: angular2/my/file.ts:79:37: Untyped property access to "get" which could be a special ts2dart builtin. Please add type declarations to disambiguate.

Your code probably looks somewhat like this:

var x;
// ... some code, maybe setting `x` to a value ...

var sth = x.get('something');

To fix the problem, add a type declaration to x, so that the expression that you call get on has a known, specific type:

var x: Injector;
// ... rest of the code is unchanged

The same applies to push, map, and so on.