title: How to specify my 'environment' in ESLint?
body: <p>I'm currently using <a href="https://github.com/eslint/eslint" rel="nofollow noreferrer">ESLint</a> in my project, and have configured it to run inside VSCode, and enforce a custom ruleset.  So far it is working as expected, and flagging lines in my code where violations occur.  I now need to specify that the <code>environment</code> is <code>browser</code> (as suggested in the solution to <a href="https://github.com/eslint/eslint/issues/4015" rel="nofollow noreferrer">this issue</a>).  How exactly do I do that, yet keep everything else about ESLint working as-is?</p>
  
  <ul>
  <li>That GitHub issue indicates I need to edit my <code>.eslintrc</code> file.  But I don't see any such file in the root of my project.  I <em>do</em> see <code>.eslint</code> files in several different dependencies, e.g. </li>
  </ul>
  
  <p><code>C:\Users\snarl\development-snarl\development-wordpress\linting-wordpress\node_modules\is-callable</code></p>
  
  <p>I could be wrong, but those don't seem related.</p>
  
  <ul>
  <li>I tried creating a new file--<code>.eslintrc.json</code>--in the root of my project, and adding to that file:</li>
  </ul>
  
  <p><code>{
      "env": {
        "browser": true
      }
   }</code></p>
  
  <p>But when I did this, and re-checked ESLint inside VSCode, it stopped flagging the rules in my custom ruleset (<a href="https://i.imgur.com/GEcPnWg.jpg" rel="nofollow noreferrer">examples</a>), and actually flagged a new rule (<a href="https://i.imgur.com/tHIVUIy.jpg" rel="nofollow noreferrer">screenshot</a>).  This seems to completely supersede some of my existing ESLint settings, rather than supplement them.</p>
  
  <p>Thanks.</p>