Fixed uninitialized flex warning

Based on the discussion around https://discordapp.com/channels/740090768164651008/745777196911689748/880301261231099944
Also turned out warning is already here, but it doesn't work, so I fixed it
Feels a bit hacky to me, but I think it's good enough

src/context.ts

@@ -8,6 +8,7 @@ export interface SharedFlexContext {
   requestReflow(): void
   registerBox(node: YogaNode, group: Group, flexProps: R3FlexProps, centerAnchor?: boolean): void
   unregisterBox(node: YogaNode): void
+  notInitialized?: boolean
 }
 
 const initialSharedFlexContext: SharedFlexContext = {
@@ -21,6 +22,7 @@ const initialSharedFlexContext: SharedFlexContext = {
   unregisterBox() {
     console.warn('Flex not initialized! Please report')
   },
+  notInitialized: true,
 }
 
 export const flexContext = createContext<SharedFlexContext>(initialSharedFlexContext)
@@ -29,11 +31,13 @@ export interface SharedBoxContext {
   node: YogaNode | null
   size: [number, number]
   centerAnchor?: boolean
+  notInitialized?: boolean
 }
 
 const initialSharedBoxContext: SharedBoxContext = {
   node: null,
   size: [0, 0],
+  notInitialized: true,
 }
 
 export const boxContext = createContext<SharedBoxContext>(initialSharedBoxContext)

src/hooks.ts

@@ -2,9 +2,9 @@ import { useCallback, useContext as useContextImpl, useMemo } from 'react'
 import { Mesh, Vector3 } from 'three'
 import { flexContext, boxContext } from './context'
 
-export function useContext<T>(context: React.Context<T>) {
+export function useContext<T extends { notInitialized?: boolean }>(context: React.Context<T>) {
   let result = useContextImpl(context)
-  if (!result) {
+  if (result.notInitialized) {
     console.warn('You must place this hook/component under a <Flex/> component!')
   }
   return result