What is JSI?

It's an interface which enables JavaScript (whether it's JSC or Hermes) to communicate with native (C++) and vice versa.

Hence using this we can eliminate the bridge. Instead we can take the following route.

Android : Java <-> JNI <-> JSI <-> Javascript.
iOS : ObjC <-> JSI <-> Javascript.

Benchmarking JSI

1. RN version: 0.63.4
2. NDK Version: 22.0.x
3. CMake Version: 3.10.x
4. Test Device : Samsung S10

Operations

1. Get String from KV store:
   1. Android Shared Prefs over JSI
   2. Async Storage
   3. Android Shared Pref over Bridge
2. Retrieve a Java String
   1. JSI
   2. Bridge
3. Retrieve a Java Object
   1. JSI
   2. Bridge
4. Query 100 Rows from Table
   1. JSI
   2. Bridge

Results:

1. Get a JSON string of 212148 characters from KV Store

   1. JSI (Async - Spawn a thread on Java)= ~ 5 MS (Min 2 MS - Max 8 MS)
   2. JSI (Sync)= ~ 2 MS (Min 1 MS - Max 3 MS)
   3. Async Storage = ~ 22 MS (Min 12 - Max 35 MS))
   4. Bridge = ~ 14 MS (Min 8 MS - Max 20 MS)

2. Get a Java String to JS through JNI and JSI

   1. JSI = <= 1 MS (Min 0 MS - Max 1 MS)
   2. Bridge = ~ 8 MS (Min 6 MS - Max 15 MS)

3. Get a Java Object (Two String properties) to JS through JNI and JSI

   1. JSI = <= 1 MS (Min 0 MS - Max 1 MS)
   2. Bridge = ~ 14 MS (Min 10 MS - Max 18 MS)

4. Query 100 rows of students in a class table - (Query time is ~ 5-10 MS)

   1. JSI = ~ 15 MS (Min 10 MS - Max 20 MS ) - Cursor iteration on Java.
   2. JSI = ~ 22 MS (Min 15 MS - Max 30 MS) - Cursor iteration on JS.
   3. Bridge = ~ 45 MS (Min 30 MS - Max 60 MS)

License

MIT