scalajs-weakreferences provides a correct implementation of java.lang.ref.WeakReference and java.lang.ref.ReferenceQueue in Scala.js.

It assumes that the target platform supports JavaScript's WeakRef and FinalizationRegistry, which are becoming standard in ECMAScript 2021. Attempts to use WeakReference or ReferenceQueue will throw ReferenceErrors if they are not supported.

Add the following dependency to your project settings:

libraryDependencies += ("org.scala-js" %%% "scalajs-weakreferences" % "1.0.0").cross(CrossVersion.for3Use2_13)

When using a crossProject, add the above in .jsSettings(...).

You can then use java.lang.ref.WeakReference and java.lang.ref.ReferenceQueue.

scalajs-weakreferences is distributed under the Apache 2.0 license, like Scala.js itself.