title: How to add values to Map<string, Set<string>> in Typescript?
body: <p>I have a map of type Map> , I need to add values to the Set multiple times : </p>
  
  <pre><code>Fields = new Map&lt;string, Set&lt;string&gt;&gt;();
  
   this.array1.forEach(s =&gt; this.Fields.set(`${s.id}`, Utils1.otherFields(s)));
   this.array2.forEach(s =&gt; this.Fields.set(`${s.id}`, Utils2.otherFields2(s)));
  </code></pre>
  
  <p>now the loop does the job perfectly , but when I return the Map , it only has the last values set in it , which is in this case values from otherFields2.</p>
  
  <p>what am I doing wrong ?</p>