I adding header in apollo gql client but the it is throwing error "Error: Failed to execute 'fetch' on 'Window': Invalid value"

import { setContext } from '@apollo/client/link/context';

const setheader = setContext((request, previousContext) => {
    let head: any = {};
    head.categoryName = localStorage.getItem('categoryName');
    return head;
});

const link = new HttpLink({
    headers: {categoryName : localStorage.getItem('categoryName')}
});

export const client = new ApolloClient({
    uri: 'url Hidden',
    cache: new InMemoryCache(),
    link,
}) as any;

apllo gql

I am adding context and link to add that while exporting the client

the error says

"Error: Failed to execute 'fetch' on 'Window': Invalid value"

and it's not valid JSON.

as per documentation it looks correct please have look and help me