>.</span><span class="hl-5">set</span><span class="hl-2">(</span><span class="hl-6">&quot;three&quot;</span><span class="hl-2">, </span><span class="hl-7">3</span><span class="hl-2">);</span><br/><span class="hl-2">  </span><span class="hl-0">// now map.size === 3</span><br/><span class="hl-2">  </span><span class="hl-0">// and map.get(&quot;two&quot;) === 2</span><br/><span class="hl-2">  </span><span class="hl-0">// and map.has(&quot;zero&quot;) === false</span>
</code><button>Copy</button></pre>
<p>You c