Created
April 30, 2020 20:06
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import React from 'react'; | |
// Create the hook that contains state as you normally would, don't worry about context | |
// Note that this is _not_ exported | |
const useSomeState = () => { | |
const [someState, setSomeState] = React.useState(); | |
return { | |
someState, | |
setSomeState, | |
}; | |
}; | |
// Use ReturnType to infer what the useSomeState hook returns | |
// https://www.typescriptlang.org/docs/handbook/utility-types.html#returntypet | |
// This is also not exported | |
const SomeContext = React.createContext<ReturnType< | |
typeof useSomeState | |
> | null>(null); | |
// Export a provider where the value is always supplied | |
export const SomeContextProvider: React.FC<{ | |
children: React.ReactNode; | |
}> = ({ children }) => { | |
const someContextValue = useSomeState(); | |
return ( | |
<SomeContext.Provider value={someContextValue}> | |
{children} | |
</SomeContext.Provider> | |
); | |
}; | |
// Export a hook that consumes the above provider | |
// Throw if context was not found | |
export const useSomeContext = () => { | |
const context = React.useContext(SomeContext); | |
if (!context) { | |
throw new Error( | |
'useSomeContext must be used within a SomeContextProvider', | |
); | |
} | |
return context; | |
}; |
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