code>key</code>, or add a new value if it isn't there. <a href="dart-collection/MapMixin/putIfAbsent.html">[...]</a>
                  <div class="features">override</div>
</dd>
        <dt id="remove" class="callable">
          <span class="name"><a href="dart-collection/MapMixin/remove.html">remove</a></span><span class="signature">(<wbr><span class="parameter" id="remove-param-key"><span class="type-annotation"><a href="dart-core/Object-class.html">Object</a></span> <span class="parameter-name">key</spa