r><th class="right">returns</th><td><code><span class="keyword">undefined</span> <span class="operator">|</span> <span class="builtin">number</span></code></td><td><p></p><p>The numeric value of the <a href="/api/metrics/type-aliases/metric/metric/"><code>Metric</code></a>, or <code>undefined</code>.</p><p></p></td></tr></table></div><p>If the identified <a href="/api/metrics/type-aliases/metric/metric/"><code>Metric</code></a> does not exist (or if the definition references a <a href="/api/store/type-alias