</span> child<span class="hl kwc">[key]</span> <span class="hl opt">=</span> parent<span class="hl kwc">[key]</span><span class="hl opt">; }</span> <span class="hl kwa">function</span> <span class="hl kwd">ctor</span><span class="hl opt">() {</span> <span class="hl kwa">this</span><span class="hl opt">.</span>constructor <span class="hl opt">=</span> child<span class="hl opt">; }</span> ctor<span class="hl opt">.</span><span class="hl kwa">prototype</span> <span class="hl opt">=</span> parent<span class="hl