What does the outside mean in darth?

Question

What does externalDart mean ? For instance:external DateTime._now();

I'm new to Dart, I can't find documentation for external, so can you give an example to help explain?

Answer 1

9.4 External functions
An external function is a function whose body is provided separately from its declaration. An external function may be a top-level function (17), a method

The body of a function is defined elsewhere.
As far as I know, this is used to fix various implementations for Dart VM in the browser and Dart VM on the server.