swyxio

// create context with no upfront defaultValue
// without having to do undefined check all the time
function createCtx<A>() {
  const ctx = React.createContext<A | undefined>(undefined)
  function useCtx() {
    const c = React.useContext(ctx)
    if (!c) throw new Error("useCtx must be inside a Provider with a value")
    return c
  }
  return [useCtx, ctx.Provider] as const

jaredpalmer

import * as React from 'react';

/**
 * React.Ref uses the readonly type `React.RefObject` instead of
 * `React.MutableRefObject`, We pretty much always assume ref objects are
 * mutable (at least when we create them), so this type is a workaround so some
 * of the weird mechanics of using refs with TS.
 */
export type AssignableRef<ValueType> =
  | {