title: map over properties in array and concat a string in JavaScript es6
body: <p>I have the following array of objects for example some authors and I want to map through them and return a string which has been concatenated with some formatting. I am for some reason having an issue with this fairly easy thing.</p>
  
  <pre><code>const authors = [ { id: 1, name: 'Steven'}, {id: 2, name: 'Nick'}]
  let names = authors.map( (a, i) =&gt; {
    return `${a.name} is cool`
  })
  console.log(names)
  // ["Steven is cool","Nick is cool"]
  // but I really want the string "Steven is cool Nick is cool"
  </code></pre>
  
  <p>How can I instead get this to map through and format it to a string? </p>
  
  <p>e.g. <code>"Steven is cool Nick is cool"</code></p>