Tests whether the specified object o has a property p on itself or
in its prototype chain.
Tests whether the specified object o has a property p on itself or
in its prototype chain.
This method is the equivalent of p in o in JavaScript.
Returns the names of all the enumerable properties of the specified
object o, including properties in its prototype chain.
Returns the names of all the enumerable properties of the specified
object o, including properties in its prototype chain.
This method returns the same set of names that would be enumerated by a for-in loop in JavaScript, in the same order.
This method assumes that all keys enumerated by a for-in loop are
strings. If this is not the case, calling this method is an undefined
behavior of kind ClassCastException. Note that for all *ordinary*
objects, the ECMAScript 2015 guarantees that this is the case. It might
be false if o is a proxy object or another exotic object.
For ordinary objects, if the underlying implementation guarantees an order for for-in loops, then this is guaranteed to be consistent with js.Object.keys, in the sense that the list returned by js.Object.keys is a sublist of the list returned by this method (not just a subset).