an class="token keyword">let</span> states <span class="token operator">=</span> <span class="token punctuation">[</span>hawaii<span class="token punctuation">,</span> california<span class="token punctuation">]</span><span class="token punctuation">;</span>

states<span class="token punctuation">.</span><span class="token function">mapBy</span><span class="token punctuation">(</span><span class="token string">'capital'</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<