./map/prototype-filter.html"><emu-note type="editor"><span class="note">Editor's Note</span><div class="note-contents">
  This code serves as placeholder until formal spec is written for this method.
</div></emu-note><emu-alg><ol><li>Let <var>map</var> be the <emu-val>this</emu-val> value.<ol><li>If Type(<var>map</var>) is not Object, throw a <emu-val>TypeError</emu-val> exception.</li><li>If <var>map</var> does not have a <emu-const><var class="field">[[MapData]]</var></emu-const> internal slot, throw a <e