r>).</li></ol></li><li>Else,<ol><li>Let <var>start</var> be 0.</li></ol></li><li>If the <var>endExpression</var> is present, then<ol><li>Let <var>endRef</var> be the result of evaluating the <var>endExpression</var>.</li><li>Let <var>end</var> be ?&nbsp;<emu-xref aoid="GetValue" id="_ref_8"><a href="https://tc39.es/ecma262/#sec-getvalue">GetValue</a></emu-xref>(<var>endRef</var>).</li></ol></li><li>Else,<ol><li>Let <var>end</var> be <emu-val>undefined</emu-val>.</li></ol></li><li>Let <var>base</var> be ?&nb