title: eslint: no-case-declaration - unexpected lexical declaration in case block
body: <p>What is the better way to update state in this context inside a reducer?</p>
  
  <pre><code>case DELETE_INTEREST:
      let deleteInterests = state.user.interests;
      let index = deleteInterests.findIndex(i =&gt; i == action.payload);
      deleteInterests.splice(index, 1);
      return { ...state, user: { ...state.user, interests: deleteInterests } };
  </code></pre>
  
  <p>ESLint doesn't like let statements inside case blocks inside a reducer, getting:</p>
  
  <blockquote>
    <p>eslint: no-case-declaration - unexpected lexical declaration in case
    block</p>
  </blockquote>