React Context Provider Pattern

context-provider.js

import React, { useEffect } from "react";

const initialState = {
  user: null,
  loading: false,
  errorMessage: ""
};

const UserContext = React.createContext();

const userReducer = (state, action) => {
  switch (action.type) {
    case "loading": {
      return { ...state, loading: true };
    }
    case "fetched": {
      return {
        ...state,
        loading: false,
        user: action.payload
      };
    }
    case "failed": {
      return {
        ...state,
        loading: false,
        errorMessage: action.payload
      };
    }
    case "updateName": {
      return {
        ...state,
        user: { ...state.user, name: action.payload }
      };
    }
    case "updatePhone": {
      return {
        ...state,
        user: { ...state.user, phone: action.payload }
      };
    }
    case "updateAddress": {
      return {
        ...state,
        user: {
          ...state.user,
          address: { ...state.user.address, ...action.payload }
        }
      };
    }

    default: {
      throw new Error(`Unhandled action type: ${action.type}`);
    }
  }
};

const UserProvider = ({ children }) => {
  const [state, dispatch] = React.useReducer(userReducer, initialState);

  useEffect(() => {
    (async () => {
      dispatch({ type: "loading" });
      try {
        const user = await new Promise((resolve, reject) => {
          setTimeout(() => {
            resolve({
              name: "Test User",
              gender: "Male",
              phone: "+910000000000",
              address: {
                building: "2030",
                street: "something something",
                location: "Some",
                country: "India"
              }
            });
          }, Math.ceil(Math.random() * 1000));
        });
        dispatch({ type: "fetched", payload: user });
      } catch (error) {
        dispatch({ type: "failed", errorMessage: "Not able to fetch user" });
      }
    })();
  }, [dispatch]);

  return (
    <>
      {state.loading && <h1>Fetching User...</h1>}
      {state.errorMessage && <h1>{state.errorMessage}</h1>}
      {state.user && (
        <UserContext.Provider value={{ state, dispatch }}>
          {children}
        </UserContext.Provider>
      )}
    </>
  );
};

const useUser = () => {
  const context = React.useContext(UserContext);
  if (context === undefined) {
    throw new Error("Error");
  }
  return context;
};

export { UserProvider, useUser };

Index.js

import React from "react";
import { useUser, UserProvider } from "./user-context";

const Address = () => {
  const {
    state: {
      user: { address }
    }
  } = useUser();
  return (
    <>
      <h3>
        {address.building}, {address.street}
      </h3>
      <h3>
        {address.location}, {address.country}
      </h3>
    </>
  );
};
const Information = () => {
  const {
    state: { user }
  } = useUser();
  return (
    <h2>
      {user.name}, {user.gender}, {user.phone}
    </h2>
  );
};

const Display = () => {
  return (
    <div className="displayCard">
      <Information />
      <Address />
    </div>
  );
};

const EditableInformation = () => {
  const {
    state: { user },
    dispatch
  } = useUser();

  return (
    <div className="personal">
      Name:{" "}
      <input
        value={user.name}
        type="text"
        onChange={e =>
          dispatch({ type: "updateName", payload: e.target.value })
        }
      />
      Name:{" "}
      <input
        type="text"
        value={user.phone}
        onChange={e =>
          dispatch({ type: "updatePhone", payload: e.target.value })
        }
      />
    </div>
  );
};

const Editable = () => {
  return (
    <div className="editable">
      <EditableInformation />
    </div>
  );
};

export default function App() {
  return (
    <div className="App">
      <UserProvider>
        <Display />
        <Editable />
      </UserProvider>
    </div>
  );
}

Working Example is here
In this, I have implemented both the things, you can read the user information through the context API, and also you can update it though I would not suggest to do the write operation like this.

IMO, Context API is very useful for a read-only state like logged in user information or preferred language across the application.
Although when we allow update from the child components, it might create a mess plus it would cause difficulties while debugging like who changed the state and when.

Click here for more information