Triggering Custom Events with Web Storage API & TypeScript

StorageListener.ts

enum StorageKey {
    SESSION_STORAGE_KEY = "auth",
    TEMP_SESSION_STORAGE_KEY = "temp_auth",
    GET_SESSION = "get_session",
    CLEAR_SESSION = "clear_session",
}

const triggerAction = (key: StorageKey) => {
    localStorage.setItem(key, "indifferent");
    localStorage.removeItem(key);
}

/**
 * Trigger for cleaning the session
 */
export const clearSession = () => {
    if (sessionStorage.length) {
        triggerAction(StorageKey.CLEAR_SESSION);
    }
}

/**
 * Trigger for start asking session data to other tabs
 */
const getSession = () => {
    if (!sessionStorage.length) {
        triggerAction(StorageKey.GET_SESSION);
    }
}

/**
 * Copy current session data from sessionStorage into the temp storage in localStorage
 * @param storageKey Session storage key where the session is stored
 */
const copySession = (storageKey: string) => {
    const sessionData = sessionStorage.getItem(storageKey);

    if (sessionData) {
        localStorage.setItem(StorageKey.TEMP_SESSION_STORAGE_KEY, JSON.stringify(sessionData));
        localStorage.removeItem(StorageKey.TEMP_SESSION_STORAGE_KEY);
    }
}

/**
 * Set data into the session storage object
 * @param storageKey Session storage key where the session will be stored
 * @param data Value for saving into the session storage object
 */
const setSession = (storageKey: string, data: string) => {
    const sessionData = JSON.parse(data);

    if (sessionData) {
        sessionStorage.setItem(storageKey, sessionData);
    }
}

const removeSession = () => {
    sessionStorage.clear();
}

const storageHandler = (storageKey: string) => (event: StorageEvent) => {
    if (!event.newValue) {
        return;
    }

    // Tab is requesting session
    if (StorageKey.GET_SESSION === event.key) {
        copySession(storageKey);
        // Tab is sending the temporal data and there is no session yet
    } else if (StorageKey.TEMP_SESSION_STORAGE_KEY === event.key && !sessionStorage.length) {
        setSession(storageKey, event.newValue);
        // Tab is cleaning some session
    } else if (StorageKey.CLEAR_SESSION === event.key) {
        removeSession();
    }
}

export const storageListener = (storageKey = StorageKey.SESSION_STORAGE_KEY) => {
    window.addEventListener("storage", storageHandler(storageKey));
    getSession();
};