Get and set localStorage with WebDriverJS `executeScript` and `executeAsyncScript`.

webdriverjs_localstorage.js

'use strict';

/**
 * Module dependencies.
 */
const webdriver = require('selenium-webdriver');

/**
 * Build driver.
 */
const builder = new webdriver.Builder();
const driver = builder.forBrowser('phantomjs').build();

// make sure to open a page otherwise you will get the WebDriverError
// SecurityError: DOM Exception 18
driver.get('https://httpbin.org');

/**
 * Set local storage item with `executeScript`.
 */
driver
    .executeScript('return window.localStorage.setItem("key", "value");');

/**
 * Get local storage item with `executeScript`.
 */
driver
    .executeScript('return window.localStorage.getItem("key");')
    .then((itemValue) => {
        console.log(itemValue);
    });

/**
 * Set and get local storage item with `executeAsyncScript`.
 */
driver
    .executeAsyncScript(function(callback) {
        window.localStorage.setItem('foo', 'bar');
        callback(window.localStorage.getItem('foo'));
    })
    .then((itemValue) => {
        console.log(itemValue);
    });

// close the driver
driver.quit();