accounts-frontend/src/components/user/middlewares/bearerHeaderMiddleware.js

// @flow
import { getActiveAccount } from 'components/accounts/reducer';

/**
 * Applies Bearer header for all requests
 *
 * req.options.token is used to override current token.
 * Pass null to disable bearer header at all
 *
 * @param {object} store - redux store
 * @param {function} store.getState
 *
 * @return {object} - request middleware
 */
export default function bearerHeaderMiddleware(store: { getState: () => Object }) {
    return {
        before<T: {
            options: {
                token?: ?string,
                headers: Object,
            }
        }>(req: T): T {
            const activeAccount = getActiveAccount(store.getState());

            let {token} = activeAccount || {};

            if (req.options.token || req.options.token === null) {
                token = req.options.token;
            }

            if (token) {
                req.options.headers.Authorization = `Bearer ${token}`;
            }

            return req;
        }
    };
}