Forgive me for golfing it, but
function getAllPropertyNames(o) {
if (!o) return [];
return Object.getOwnPropertyNames(o) +
getAllPropertyNames(Object.getPrototypeOf(o));
}
or as a generator
function* allPropertyNames(o) {
if (!o) return;
yield* Object.getOwnPropertyNames(o);
yield* allPropertyNames(Object.getPrototypeOf(o));
}
don't seem too onerous.
Though on the other hand, didn't I hear that prototype loops are now
possible with Proxies? If so, then you'd need to handle that.
Then again, if you're going to handle weird cases, then what should it
even return if you go through a Proxy's getPrototypeOf trap that mutates
the set of properties?
On 05/31/2015 04:42 AM, Gray Zhang wrote:
Since class’s members are non-enumerable by default (which is a good
choice) we cannot use |for .. in| to iterate over all members of an
instance, the same problem could exists in a plain object when we use
|Object.defineProperty| API.
In real world there are some scenarios where we need to iterate over
members, A common example is we need to find all |set{SomeThing}|
methods so we can do an auto dependency injection.
Certainly we can write a 3rd-party function to find all members
through prototype chain:
|function getAllMembersKeys(obj) {
let keys = [];
while (obj) {
keys.push(...Object.getOwnPropertyNames(obj));
obj = Object.getPrototypeOf(obj);
}
return keys;
}
|
But it doesn’t look nice and lacks considerations of many things such
as Symbol’d keys.
Look around other languages with reflection API, most of them would
provide a method to iterate over all members / properties / methods of
an instance, so why not we provide a set of utility API:
* |Reflect.getAllMembersNames|
* |Reflect.getAllMemberDescriptors|
* |Reflect.getAllMethodNames|
* |Reflect.getAllMethodDescriptors|
* |Reflect.getAllPropertyNames|
* |Reflect.getAllPropertyDescriptors|
------------------------------------------------------------------------
Best regards
Gray Zhang
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