Transmit

A very simple global message-passing library for dart/js interop, based on custom events. It's particularly useful as a two way communication system between dart and Js contexts.

Dart API

a Service receives all messages created by a following transmit with a matching type

Service(List<String> types, Function target);

transmit(String type, var content);

Example

main() {
    new Service(['pokemon'], choose);
    new Service(['attack'], waterGun);

    // Messages trigger services that contain their types.
    transmit('pokemon', 'Squirtle');
        // => I choose you Squirtle!
    transmit('attack', 'Squirtle');
        // => Squirtle used Water Gun!
}

waterGun(content) {
    print('${content} used Water Gun!');
}

choose(content) {
    print('I choose you ${content}!');
}

Cancelling a Service

Cancel services any time you want it to stop running the callback. In order to cancel a Service, you'll need to store it in a Service variable.

In this example, the service will run once, because it cancels itself. Notice that the Service variable is declared before it is defined, allowing the callback to access it.

main() {
    Service myService;
    myService = new Service(['rattata'], (_) {
        // code here will only run on the first transmit(),
        // because this line turns off the Service:
        myService.cancel();
    });
}

Cancel Services from anywhere the declared Service is accessible:

import "dart:html";

Service myPublicService;
    
main() {
    myPublicService = new Service(['trapinch'], (_) {
        print("Trapinch never made it live");
    });
        
    querySelector("#myButton").onClick.first.then((_) => stopListening());
}
    
void stopListening() {
    myPublicService.cancel();
}

JS API

transmit(String type, content);