Using dart to create a javascript library
Even though Dart supports this use case, if you target JavaScript developers I would stick with JavaScript.
@AlexandreArdhuin shows in his answer to Expose Dart functions to javascript how you can make a Dart function available to JavaScript.
Under the dart-js-interop are many examples how to do function calls and pass data between Dart and JavaScript.
Wrap dart class into custom element, the Dart object auto expose to javascript. Assume we have 2 Dart Classes, SlickGrid Class contains Column class in Dart
class SlickGrid{ List<Column> columns;}class Column{}class GridWrap extends HtmlElement { ShadowRoot shadowRoot; SlickGrid grid; // here is your cool object}compile to javascript, and register custom element, then open javascript console,
//this is SlickGrid objectvar grid= document.querySelector('cj-grid').grid; // this is dart Column Objectvar column = grid.columns.$index(0,0); // call toString function in dart object that produce json string...column.toString$0()