title: Material-UI TextField context dirty
body: <p>I'm trying to better understand how to check for dirtyness using material-ui's FormControl or TextField component. The documentation for <a href="https://material-ui-next.com/demos/text-fields/#components" rel="noreferrer">TextField demo page</a> states:</p>
  
  <blockquote>
    <p>TextField is composed of smaller components (FormControl, InputLabel,
    Input, and FormHelperText) that you can leverage directly to
    significantly customize your form inputs.</p>
  </blockquote>
  
  <p>... and on the <a href="https://material-ui-next.com/api/text-field/#inheritance" rel="noreferrer">TextField API docs</a> it states:</p>
  
  <blockquote>
    <p>The properties of the <code>&lt;FormControl /&gt;</code> component are also available.</p>
  </blockquote>
  
  <p>... and later in the <a href="https://material-ui-next.com/api/form-control/#formcontrol" rel="noreferrer">FormControl API docs</a> it states:</p>
  
  <blockquote>
    <p>Provides context such as <strong>dirty</strong>/focused/error/required for form inputs.
    Relying on the context provides high flexibilty and ensures that the
    state always stay consitent across the children of the FormControl.
    This context is used by the following components:</p>
    
    <p>FormLabel
    FormHelperText
    Input
    InputLabel</p>
  </blockquote>
  
  <hr>
  
  <p>But I don't see any documentation state exactly HOW to check for dirty using the TextField / FormControl.</p>
  
  <p>Can anyone clarify? This is StackOverflow, so here is some code for the TextField I'm using:</p>
  
  <pre><code>&lt;TextField
    id='email'
    label='Email'
    value={this.state.email}
    onChange={this.handleChange('email')}
    margin="normal"
    required
    fullWidth&gt;
  &lt;/TextField&gt;
  </code></pre>