fix: stringify less when processing recordindgs

frontend/src/scenes/session-recordings/player/sessionRecordingDataLogic.ts

@@ -125,6 +125,27 @@ const getHrefFromSnapshot = (snapshot: RecordingSnapshot): string | undefined =>
     return (snapshot.data as any)?.href || (snapshot.data as any)?.payload?.href
 }
 
+/*
+    cyrb53 (c) 2018 bryc (github.com/bryc)
+    License: Public domain. Attribution appreciated.
+    A fast and simple 53-bit string hash function with decent collision resistance.
+    Largely inspired by MurmurHash2/3, but with a focus on speed/simplicity.
+*/
+const cyrb53 = function (str: string, seed = 0): number {
+    let h1 = 0xdeadbeef ^ seed,
+        h2 = 0x41c6ce57 ^ seed
+    for (let i = 0, ch; i < str.length; i++) {
+        ch = str.charCodeAt(i)
+        h1 = Math.imul(h1 ^ ch, 2654435761)
+        h2 = Math.imul(h2 ^ ch, 1597334677)
+    }
+    h1 = Math.imul(h1 ^ (h1 >>> 16), 2246822507)
+    h1 ^= Math.imul(h2 ^ (h2 >>> 13), 3266489909)
+    h2 = Math.imul(h2 ^ (h2 >>> 16), 2246822507)
+    h2 ^= Math.imul(h1 ^ (h1 >>> 13), 3266489909)
+    return 4294967296 * (2097151 & h2) + (h1 >>> 0)
+}
+
 export const deduplicateSnapshots = (
     newSnapshots?: RecordingSnapshot[],
     existingSnapshots?: RecordingSnapshot[]
@@ -141,7 +162,11 @@ export const deduplicateSnapshots = (
             // we can see duplicates that only differ by delay - these still count as duplicates
             // even though the delay would hide that
             const { delay: _delay, ...delayFreeSnapshot } = snapshot
-            const key = JSON.stringify(delayFreeSnapshot)
+            // we check each item multiple times as new snapshots come in
+            // so store the computer value on the object to save recalculating it so much
+            const key = (snapshot as any).seen || cyrb53(JSON.stringify(delayFreeSnapshot))
+            ;(snapshot as any).seen = key
+
             if (seenHashes.has(key)) {
                 return false
             } else {