localstorage-02.js

/**
 * Saves an item in localStorage so it can be retrieved later.  This method automatically encodes the value as JSON, so you don't have to.  If you don't supply a value, this method will return false immediately.
 *
 * @example <caption>set localStorage that persists until it is manually removed</caption>
 * LocalStorage.setItem('key', 'value');
 *
 * @example <caption>set localStorage that persists for the next 30 seconds before being busted</caption>
 * LocalStorage.setItem('key', 'value', 30);
 *
 * @kind function
 * @function LocalStorage#setItem
 *
 * @param {!string} key - Name of the key in localStorage.
 * @param {!*} value - Value that should be stored in localStorage.  Must be able to be encoded/decoded as JSON.  Please ensure your object doesn't have the key __expiry as this will accidentally conflict with the expiry handler.
 * @param {?int} [expiry=null] - Time in seconds that the localStorage cache should be considered valid.
 * @returns {boolean} Returns true if it was stored in localStorage, false otherwise.
 */
setItem: function (key, value, expiry) {
    if (!this.supportsLocalStorage() || typeof value === 'undefined' || key === null || value === null) {
        return false;
    }

    if (typeof expiry === 'number') {
        value = {
            __data: value,
            __expiry: Date.now() + (parseInt(expiry) * 1000)
        };
    }

    try {
        localStorage.setItem(key, JSON.stringify(value));

        return true;
    } catch (e) {
        console.log('Unable to store ' + key + ' in localStorage due to ' + e.name);

        return false;
    }
}