xpression</var> (a <emu-xref href="#sec-syntactic-grammar"><a href="https://tc39.es/ecma262/#sec-syntactic-grammar">Parse Node</a></emu-xref>). It performs the following steps:</p>
      <emu-alg><ol><li>If the <var>startExpression</var> is present, then<ol><li>Let <var>startRef</var> be the result of evaluating the <var>startExpression</var>.</li><li>Let <var>start</var> be ?&nbsp;<emu-xref aoid="GetValue" id="_ref_7"><a href="https://tc39.es/ecma262/#sec-getvalue">GetValue</a></emu-xref>(<var>startRef</va