Created attachment 475167 [details] Full reproduction The result of this bug is that keys are incorrectly computed in WebKit and Safari. Reads based on key or range are not accurate. Reproducible with the following setup: Create an object store with key path consisting of two or more fields. ``` const openDBRequest = indexedDB.open(dbName, version); let db; openDBRequest.onupgradeneeded = event => { db = event.target.result; if (!db.objectStoreNames.contains(storeName)) { const objectStore = db.createObjectStore(storeName, { keyPath: ['bar', 'baz'] }); } }; ``` Add data, where any field but the last field in the key is a typed array value. ``` const transaction = db.transaction([storeName], 'readwrite'); const objectStore = transaction.objectStore(storeName); const put = objectStore.put({ bar: new Uint8Array([1,2,3]), baz: 1 }); ``` Read the key for the value you just wrote and see that the key value representing `bar` is not an accurate representation of the value on the object. ``` objectStore.getAllKeys().onsuccess = evt => { const idbValidKeys = evt.target.result; idbValidKeys.forEach(idbValidKey => { // UNEXPECTED BEHAVIOR: // Should equal new Uint8Array([1, 2, 3]) console.log(new Uint8Array(idbValidKey[0])); // This is right console.log(idbValidKey[1]); }); }; ``` A full reproduction is attached.