Bridges to react native
Crossing the gap by writing native modules
hello, I'm Florian ๐
Software engineer @
Developer of
and
@florianrival
4ian
you've said
Bridges?
Let's see how they do
Node.js?
Java?
emscripten?
react native?
xamarin?
โ node-gyp
โ Embind/WebIDL
โ JNI
โ C# bindings generators
โ The bridge
COCOS2d-JS
โ Bindings with SpiderMonkey
react native
Bridge
in a nutshell
Quick recap
$ ls
android
ios
package.json
index.js
Your app is built in JavaScript using React
Components (or API) provided by React Native are creating native components on screen
exchanging over the bridge
Native app
JS engine
thread
Bridge
Asynchronous messages or events (sent on a batched queue)*
Main thread
Native module thread
* Will likely change soon to be synchronous :)
When calling a native method from JS
messages and arguments
from native to js
Arguments sent internally as JSON
Module id, method id and arguments queued
All useful types are supported ๐ช
Number, String, Function, Array, Object, even Promises
write a
how to
native module
start by coding in your app
Go read facebook.github.io/react-native/docs/native-modules-ios.html
Open XCode
Add an Objective-C file
Write your methods
Expose them with RCT_EXPORT_METHOD and RCT_EXPORT_MODULE
import { NativeModules } from 'react-native';
var MyModule = NativeModules.CalendarManager;
CalendarManager.addEvent('Birthday Party', '4 Privet Drive, Surrey');
Relaunch to recompile your app ๐
iOS
Expose methods with @ReactMethod
Go read https://facebook.github.io/react-native/docs/native-modules-android.html
Open Android Studio
Add a ReactPackage
Add a ReactContextBaseJavaModule
import { NativeModules } from 'react-native';
var MyModule = NativeModules.CalendarManager;
CalendarManager.addEvent('Birthday Party', '4 Privet Drive, Surrey');
Relaunch to recompile your app ๐
Android
create a module
Bootstrap an empty native module
Set up a blank React Native app
Use `file:../` in your example app to have your test bed app use the module that is in the parent directory.
npm publish
PROTIP
bootstrapping a module
https://github.com/bamlab/generator-module-react-native
https://github.com/frostney/react-native-create-library
https://github.com/peggyrayzis/react-native-create-bridge
Kotlin & Swift support!
doing native? use native tooling too!
Console output
NSLog(@"Yup, I'm working");
System.out.printLn("Howdy");
Good way to warn about missing/bad configurations:
native debuggers
View inspectors
View inspectors
Bridge profiler
https://github.com/jondot/rn-snoopy
MessageQueue.spy
Memory profiler
things that
hurt
๐
handlingย exceptions
๐
too much data over the bridge
rn-snoopy is a good way to check if that's the case or why
"congestion" on the bridge
data too bigย over the bridge
Don't send files over the bridge ๐
Keep working with filepaths
Write large chunks of data (processed images, large computation results...) in cache if needed
breakingย changes
Follow semver
Changes in the native code of React Native (headers, interfaces...) may force you to only support latest versions
Upgrade the major version when a breaking change in the interface is done
Tools like commitizen can help
stay up-to-date with rn
quick look
FUTURE
in the
of React native
and the bridge
Reworking the Architecture
We're working on a large-scale rearchitecture of React Native to make the framework more flexible and integrate better with native infrastructure in hybrid JavaScript/native apps
(emphasis mine)
https://facebook.github.io/react-native/blog/2018/06/14/state-of-react-native-2018
updating the threading model
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
(emphasis mine)
https://facebook.github.io/react-native/blog/2018/06/14/state-of-react-native-2018
incorporating async rendering
allow multiple rendering priorities and to simplify asynchronous data handling
https://facebook.github.io/react-native/blog/2018/06/14/state-of-react-native-2018
https://reactjs.org/blog/2018/03/01/sneak-peek-beyond-react-16.html
Time slicing and React "Suspense":
a leanerย bridge
[...] simplifying our bridge to make it faster and more lightweight; direct calls between native and JavaScript are more efficient
https://facebook.github.io/react-native/blog/2018/06/14/state-of-react-native-2018
thank you!
: ย ย
) ย ย
@florianrival
4ian
Bridges to React Native (2018)
By Florian Rival
Bridges to React Native (2018)
Talk at React Native London meetup
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