Why does react native use a batched communication (bridge) between native modules and javascript thread? Why aren't other options used (IPC, FFI?) and why is there limited bandwidth through the bridge?
A problem with react-native is streaming large data between JS and native module will lock up the bridge. source
I am new to this area and would like to learn more, please point me to the correct concepts, as I'm not able to find much about this.
When we started the React Native project in 2013, we designed it to have a single “bridge” between JavaScript and native that is asynchronous, serializable, and batched. Just as React DOM turns React state updates into imperative, mutative calls to DOM APIs like document.createElement(attrs) and .appendChild(), React Native was designed to return a single JSON message that lists mutations to perform, like [["createView", attrs], ["manageChildren", ...]]. We designed the entire system to never rely on getting a synchronous response back and to ensure everything in that list could be fully serialized to JSON and back. We did this for the flexibility it gave us: on top of this architecture, we were able to build tools like Chrome debugging, which runs all the JavaScript code asynchronously over a WebSocket connection.
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In summary, they did it because it was one way they could do it which gave some benefits and matched the paradigm of react. Now, they're doing the making it synchronous because it also brings benefits.
First, we are changing the threading model. Instead of each UI update needing to perform work on three different threads, it will be possible to call synchronously into JavaScript on any thread for high-priority updates while still keeping low-priority work off the main thread to maintain responsiveness. Second, we are incorporating async rendering capabilities into React Native to allow multiple rendering priorities and to simplify asynchronous data handling. Finally, we are simplifying our bridge to make it faster and more lightweight; direct calls between native and JavaScript are more efficient and will make it easier to build debugging tools like cross-language stack traces.
