Adding the rest back in.

node_modules/undici/lib/compat/dispatcher-weakref.js

@@ -0,0 +1,48 @@
+'use strict'
+
+/* istanbul ignore file: only for Node 12 */
+
+const { kConnected, kSize } = require('../core/symbols')
+
+class CompatWeakRef {
+  constructor (value) {
+    this.value = value
+  }
+
+  deref () {
+    return this.value[kConnected] === 0 && this.value[kSize] === 0
+      ? undefined
+      : this.value
+  }
+}
+
+class CompatFinalizer {
+  constructor (finalizer) {
+    this.finalizer = finalizer
+  }
+
+  register (dispatcher, key) {
+    if (dispatcher.on) {
+      dispatcher.on('disconnect', () => {
+        if (dispatcher[kConnected] === 0 && dispatcher[kSize] === 0) {
+          this.finalizer(key)
+        }
+      })
+    }
+  }
+}
+
+module.exports = function () {
+  // FIXME: remove workaround when the Node bug is fixed
+  // https://github.com/nodejs/node/issues/49344#issuecomment-1741776308
+  if (process.env.NODE_V8_COVERAGE) {
+    return {
+      WeakRef: CompatWeakRef,
+      FinalizationRegistry: CompatFinalizer
+    }
+  }
+  return {
+    WeakRef: global.WeakRef || CompatWeakRef,
+    FinalizationRegistry: global.FinalizationRegistry || CompatFinalizer
+  }
+}