fix(SW-663): Fixed leaking of live preview hash and removing preview pages

lib/previewContext.ts

@@ -0,0 +1,42 @@
+import { cache } from "react"
+
+interface PreviewData {
+  hash: string
+  uid: string
+}
+
+const getRef = cache((): { current: PreviewData | undefined } => ({
+  current: undefined,
+}))
+
+/**
+ * Set the preview hash for the current request
+ *
+ * It works kind of like React's context,
+ * but on the server side, per request.
+ *
+ * @param hash
+ */
+export function setPreviewData(data: PreviewData | undefined) {
+  console.log("SETTING HASH")
+  getRef().current = data
+}
+
+/**
+ * Get the preview hash set for the current request
+ */
+export function getPreviewHash() {
+  return getRef().current?.hash
+}
+
+/**
+ * Check if the current request is a preview by comparing the uid
+ */
+export function isPreview(uid?: string) {
+  const data = getRef().current
+
+  if (uid && data?.hash) {
+    return data.uid === uid
+  }
+  return false
+}