title: How can I access localStorage of Cordova App via WebdriverIO and Appium?
body: <p>I'm currently trying to write some automated tests for our cordova app written in Angular.
  My current setup is the following: </p>
  
  <p>Versions:</p>
  
  <pre><code>appium: 1.7.2
  wdio-appium-service: 0.2.3
  webdriverio: 4.11.0
  </code></pre>
  
  <blockquote>
    <p>wdio.conf.js</p>
  </blockquote>
  
  <pre class="lang-js prettyprint-override"><code>exports.config = {
    port: 4723,
    logLevel: 'error',
    capabilities: [{
      platformName: 'Android',
      platformVersion: '8.1',
      deviceName: 'any',
      app: '../cordova_app/platforms/android/app/build/outputs/apk/debug/app-debug.apk',
      autoWebview: true,
      autoGrantPermissions: true
    }],
    // specs: ['./tests/spec/**/*.js'],
    specs: ['./tests/spec/login.js'],
    services: ['appium'],
    reporters: ['spec'],
    framework: 'jasmine',
    jasmineNodeOpts: {
      defaultTimeoutInterval: 90000
    }
  }
  </code></pre>
  
  <blockquote>
    <p>tests/spec/login.js</p>
  </blockquote>
  
  <pre class="lang-js prettyprint-override"><code>
  describe('Language and market choosing process', () =&gt; {
      beforeEach(() =&gt; {
          browser.timeouts('implicit', 2000);
      });
      afterEach(() =&gt; {
          browser.reload();
      });
  
      it('should go through login process', () =&gt; {
  
          const selectCountryBtn = $('.fsr-login__market-chooser');
          selectCountryBtn.click();
          // everything works so far
  
          browser.localStorage('POST', {key: 'test', value: 'test123'}); 
          // Failed: unknown error: call function result missing 'value'
      });
  });
  </code></pre>
  
  <p>When I run this test on my Android 8.1 emulator, the test crashes as soon as it reaches the localstorage part with the error: </p>
  
  <pre><code>Failed: unknown error: call function result missing "value"
  Error: An unknown server-side error occurred while processing the command.
  at localStorage("POST", [object Object]) - index.js:316:3
  </code></pre>
  
  <p>The localStorage API of WebdriverIO is described <a href="http://v4.webdriver.io/v3.4/api/protocol/localStorage.html" rel="nofollow noreferrer">here</a></p>
  
  <p>What am I doing wrong?</p>