@observe.resolver

The @resolver decorator provides a powerful and generic interface for providing custom functionality without having to deal with the underlying observation. The resolved value is accessed on the instance as a getter.

When attached to a method, it passes an argument with several properties:

• resolve - Update the value to be the passed argument.
• listenTo - Listen for changes to this key on the instance, calling a callback when it changes.
• stopListening - Stop listening for changes to this key.
• lastSet - The last value that was set.

This example will return a value that counts how many times the value property was changed. The resolved value would be accessed as thing.count (as a getter).

import observe from "can-observe";

class Thing extends observe.Object {
    @observe.resolver
    count( { resolve, listenTo } ) {
        let count = 0;
        resolve( count );

        listenTo( "value", () => {
            resolve( ++count );
        } );
    }
}