value.returnedBy( getter )

Creates an observable value that can be read and observed using can-reflect.

The following creates a fullName observable that derives its values from the person observable. The value of the observable is read with fullName.value:

import canReflect from "can-reflect";
import value from "can-value";
import observe from "can-observe";

const person = observe( { first: "Grace", last: "Murray" } );

const fullName = value.returnedBy( function() {
    return person.first + " " + person.last;
} );
fullName.value; // is "Grace Murray"

const handler = function(newValue) {
  newValue; // is "Grace Hopper"
};
canReflect.onValue(fullName, handler);
person.last = "Hopper";

canReflect.offValue(observable, handler);