There's a conversation I had with Ron Buckton, the proposal champion, mainly on this specific issue. [1]
Short answer: Yes, Disposable can leak if you forget "using" it. And it will leak if the Disposable is not guarded by advanced GC mechanisms like the FinalizationRegistry.
Unlike C# where it's relatively easier to utilize its GC to dispose undisposed resources [2], properly utilizing FinalizationRegistry to do the same thing in JavaScript is not that simple. In response to our conversation, Ron is proposing adding the use of FinalizationRegistry as a best practice note [3], but only for native handles. It's mainly meant for JS engine developers.
Most JS developers wrapping anything inside a Disposable would not go through the complexity of integrating with FinalizationRegistry, thus cannot gain the same level of memory-safety, and will leak if not "using" it.
IMO this design will cause a lot of problems, misuses and abuses. But making JS to look more like C# is on Microsoft's agenda so they are probably not going to change anything.
Short answer: Yes, Disposable can leak if you forget "using" it. And it will leak if the Disposable is not guarded by advanced GC mechanisms like the FinalizationRegistry.
Unlike C# where it's relatively easier to utilize its GC to dispose undisposed resources [2], properly utilizing FinalizationRegistry to do the same thing in JavaScript is not that simple. In response to our conversation, Ron is proposing adding the use of FinalizationRegistry as a best practice note [3], but only for native handles. It's mainly meant for JS engine developers.
Most JS developers wrapping anything inside a Disposable would not go through the complexity of integrating with FinalizationRegistry, thus cannot gain the same level of memory-safety, and will leak if not "using" it.
IMO this design will cause a lot of problems, misuses and abuses. But making JS to look more like C# is on Microsoft's agenda so they are probably not going to change anything.
[1]: https://github.com/tc39/proposal-explicit-resource-managemen...
[2]: https://stackoverflow.com/a/538238/1481095
[3]: https://github.com/tc39/proposal-explicit-resource-managemen...