title: How to disable "Use Strict" in Jest
body: <p>I am writing some unit tests for a codebase which uses octal literals. Whenever the test is executed with <code>npm test</code>, a syntax error appears as follows:</p>
  <blockquote>
  <p>Legacy octal literals are not allowed in strict mode.</p>
  </blockquote>
  <p>I should stress that <code>&quot;use strict&quot;</code> does not appear anywhere in the source code, nor can I identify any option in <code>package-lock.json</code> or <code>package.json</code> indicating strict mode. Both JSON files were created with the <code>npm init -y</code> and received no further modification except the addition of:</p>
  <pre class="lang-json prettyprint-override"><code>  &quot;scripts&quot;: {
      &quot;test&quot;: &quot;jest&quot;
    },
  </code></pre>
  <p>How can I force Jest out of strict mode in order to test code with legacy octal literals?</p>