guojenman / react-obs

A react store built on top of rxjs & hooks

react-obs

A react store built on top of rxjs & hooks

goals

• Familiar - useState() like API
• No magic, just streams
• Render only components whose values that have changed, no other components are re-rendered
• Don't need to know rxjs to use with react-obs, but you can if you want to
• Small, minimal library

install

npm i react-obs rxjs --save

usage

See examples folder for a working demos

Store

class AppStore {
  
  test1 = makeObs(0);
  doubleTest1 = computed(
    ([v]) => v * 2, [this.test1]
  );
  
}
export const appStore = new AppStore();
// we pass appStore here just for intellisense, but the real value is passed to the Provider
export const AppContext = React.createContext(appStore);

Provide the store for you app

ReactDOM.render(
  <AppContext.Provider value={appStore}>
    <App />
  </AppContext.Provider>
, document.getElementById('root'));

A child Component somewhere down the tree

const appStore = useContext(AppContext);
const [val, setVal] = useObs(appStore.test1);
// can't set a computed value, so just the getter
const [doubleTest1] = useObs(appStore.doubleTest1);
return (
  <>
    <div>test1 value from the store is {val}</div>
    <div>and double that, is {doubleTest1}</div>
    <button onClick={() => setVal(val + 1)}>add 1</button>
  </>
)

API

• makeObs: create an observable with a default value
• useObs: consume the observale in a component with useState like API
• useObsDeep: same as useObs but with a jsonPath option to pluck and set value deeply nested in an object
• computed: watch one ore more observables and return a computed value from them

for more doc, for now read the code in index.ts, it's a tiny file.

FAQ

1. How do I mutate a value?

   myValue = makeObs(0) // creates the observable
   myValue.next(1) // mutate your data (by pushing a new value in the stream)

2. Why not using object getter/setter functions to make reading and setting values more natural?

   I wanted to keep the ability to easily use rxjs and calling getValue() & next(), seemed like small price to pay