title: what does 0,1,2 value indicate in eslintrc file?
body: <pre><code>"react/jsx-uses-vars": 2,
  </code></pre>
  
  <p>In my .eslintrc file under rules object, I've this property and other properties with value, 0, 1 and 2. What does the value 0, 1, 2 indicate? </p>