Property 'account' does not exist on type 'DataContextProps | null'

I am unable to access account or any other property from DataContextProps.

context/Datacontext.tsx

interface DataContextProps {
    account: string;
    contract: any;
    loading: any;
    images: any[];
    imageCount: number;
    updateImages: () => Promise<void>;
    donateImageOwner: (id: string, DonateAmount: any) => Promise<void>;
};

const DataContext = createContext<DataContextProps | null>(null);

interface Props {
    children?: React.ReactNode;
  };

export const DataProvider: React.FC<Props> = ({ children }) => {
    const data = useProviderData();
    return <DataContext.Provider value={data}>{children}</DataContext.Provider>;
};

export const useData = () => useContext<DataContextProps | null>(DataContext);

Header.tsx

import Identicon from "identicon";
import React, { useEffect } from "react";
import { useData } from "../../contexts/DataContext";

function Header() {
  const { account } = useData();
  const [data, setData] = React.useState();
  useEffect(() => {
    if (account !== "0x0") {
      setData(new Identicon(account, 200).toString());
    }
  }, [account]);
  return ()
}
export default Header;

it's because property account does not exist in type null, you can define an initialDataContextProps object with properties in their initial state, and remove union null from createContext generics, take this for example:

const initialDataContextProps = {
    account: "";
    contract: null;
    loading: null;
    images: [];
    imageCount: 0;
    updateImages: async () => {};
    donateImageOwner: async (id: string, DonateAmount: any) => {};
};

const DataContext = createContext<DataContextProps>(initialDataContextProps)
/* ...other code */
export const useData = () => useContext(DataContext); // no generics needed