Recos - experimental ts/jsx to Android Compose/SwiftUI compiler

This repository contains an early prototype of Recos, an experimental compiler, which would compile tx/jsx into Android Jetpack Compose and iOS SwiftUI.

For a long time, many technologies have been introduced to build cross-platform mobile apps using single codebase, and React-Native is the most popular framework in this area. However, React-Native has some kind of performance issues and relatively higher memory usage.

The main goal of Recos is to help us building high performance cross-platform mobile apps in a declarative manner.

Recos overview

Getting started with Recos

Before starting this 101 tutorial, make sure our system have installed node, and suppose we are using macOS, we may consider install it via brew:

brew install node npm install getopts --save

For the Android side, in order to make Jetpack Compose works, we must use Android Studio Preview version in this moment.

Setting up the development environment is out of the scope of this tutorial, for more information, please read the latest official docs from Facebook and Google.

Using your convenient tool to write the first React app, we will use TypeScript in this case and named it hello.tsx:

function Item1(item, onItemClick) {
    const onClick = useCallback(() => {
        onItemClick(item)
    })

    return <Text style={{ color: '#fff' }} onClick={onClick}>偶数：{item.name}, {item.count}</Text>

}

function Item2(item, onItemClick) {
    const onClick = useCallback(() => {
        onItemClick(item)
    })

    return <Text style={{ color: '#fff' }} onClick={onClick}>奇数：{item.name}, {item.count}</Text>
}

function HelloWorld(current) {

    const [data, setData] = useState([])

    useEffect(() => {
        let ret = []
        for (let i = 0; i < 1000; i++) {
            ret.push({
                name: 'item' + i,
                index: i,
                count: 0
            })
        }
        setData(ret)
    }, [current])

    let render = function (i) {
        let item = data[i]
        if (item.index % 2 == 0) {
            return Item1(item, (it) => {
                it.count = it.count + 1
                setData(data)
            })
        } else {
            return Item2(item, (it) => {
                it.count = it.count + 2
                setData(data)
            })
        }
    }

    return <RecyclerView count={data.length} render={render}>Hello World!</RecyclerView>
}

The next step would be use js/cli.js to compile it into a bundle file:

node cli.js -s hello.tsx -o hello.bundle

Put the output file hello.bundle into Android project's app/src/main/assets, compile the Android app and we will see: