@@can.valueHasDependencies()

The @@can.valueHasDependencies symbol points to a function that returns true if there are any other events or property changes that will trigger an event for the value on the context object; false otherwise. By convention, if an object implementation distinguishes between unbound objects or values, and those which are bound without external dependencies (as is the case with can-compute), @@can.valueHasDependencies may return undefined for unbound objects instead of false.

var someOtherObj;
var internalValue;
function computed(value) {
    if(arguments.length >= 1) {
        internalValue = value;
        obj.__bindEvents.forEach(function(handler) {
            handler.call(this, value);
        });
    } else {
        return internalValue;
    }
}
obj.__bindEvents = [{ 
    handler: function() {},
    reads: [{ object: someOtherObj }]
}];

obj[canSymbol.for("can.valueHasDependencies")] = function() {
    return this.__bindEvents && 
        this.__bindEvents.filter(function(binding) {
            return binding.reads && binding.reads.length > 0;
        }).length > 0;
};