Last active
          May 25, 2019 14:04 
        
      - 
      
- 
        Save modernserf/6e1534d84e219858ec23d5578921e5a3 to your computer and use it in GitHub Desktop. 
    Two approaches to handling imperative code in react
  
        
  
    
      This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
      Learn more about bidirectional Unicode characters
    
  
  
    
  | function useTransition (isActive, onEnter = noop, onExit = noop) { | |
| const ref = useRef() | |
| useEffect(() => { | |
| if (!ref.current) return | |
| if (isActive) onEnter(ref.current) else onExit(ref.current) | |
| }, [isActive]) | |
| return ref | |
| } | |
| // ----- | |
| function ScrollIntoViewContainer ({ isActive, children }) { | |
| const ref = useTransition(isActive, (el) => el.scrollIntoView()) | |
| return <div ref={ref}>{children}</div> | |
| } | 
  
    
      This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
      Learn more about bidirectional Unicode characters
    
  
  
    
  | const Context = createContext() | |
| function NamedImperativeController ({ children }) { | |
| const [refs, setRefs] = useState({}) | |
| const value = useMemo(() => ({ | |
| registerRef: (name, ref) => { | |
| if (refs[name]) throw new Error(`Already a ref with name ${name}`) | |
| setRefs(prev => ({ ...prev, [name]: ref })) | |
| return () => setRefs(prev => ({ ...prev, [name]: undefined })) | |
| }, | |
| getNamedRef: (name, onError=null) => { | |
| if (refs[name]) return refs[name] | |
| if (onError) return onError(refs) | |
| throw new Error(`No ref with name ${name}`) | |
| } | |
| }), [refs]) | |
| return <Context.Provider value={value}>{children}</Context.Provider> | |
| } | |
| function useNamedRef (name) { | |
| const ref = useRef() | |
| const { registerRef } = useContext(Context) | |
| useEffect(() => registerRef(name, ref), [name]) | |
| return ref | |
| } | |
| function useGetNamedRef (name, orDefault) { | |
| const { getNamedRef } = useContext(Context) | |
| return getNamedRef(name, orDefault) | |
| } | 
  
    Sign up for free
    to join this conversation on GitHub.
    Already have an account?
    Sign in to comment