1 files changed, 24 insertions, 0 deletions
diff --git a/app/scripts/lib/observable/util/sync.js b/app/scripts/lib/observable/util/sync.js
new file mode 100644
index 000000000..c61feb02e
--- /dev/null
+++ b/app/scripts/lib/observable/util/sync.js
@@ -0,0 +1,24 @@
+
+//
+// synchronizeStore(inStore, outStore, stateTransform)
+//
+// keeps outStore synchronized with inStore, via an optional stateTransform
+//
+
+module.exports = synchronizeStore
+
+
+function synchronizeStore(inStore, outStore, stateTransform) {
+  stateTransform = stateTransform || transformNoop
+  const initState = stateTransform(inStore.get())
+  outStore.put(initState)
+  inStore.subscribe((inState) => {
+    const outState = stateTransform(inState)
+    outStore.put(outState)
+  })
+  return outStore
+}
+
+function transformNoop(state) {
+  return state
+}
+\ No newline at end of file