mapJSFunction function
Maps a JavaScript function to a Dart function.
jsFunctionName Name of the function.
f Dart function to map.
Implementation
void mapJSFunction(String jsFunctionName, MappedFunction f) {
globalContext[jsFunctionName] = (JSAny a) {
Object? r = f(a.dartify());
return r.jsify();
}.toJS;
}