title: what does the symbol '$' mean in angular?
body: <p>What does mean by <strong>$</strong> in ${some_var}</p>
  
  <pre><code>search(term:string) {
          let promise = new Promise((resolve, reject) =&gt; {
          let apiURL = `${this.apiRoot}?term=${term}&amp;media=music&amp;limit=20`;
          this.http.get(apiURL)
              .toPromise()
              .then(
              res =&gt; { // Success
                  console.log(res.json());
                  resolve();
                     }
                   );
          });
          return promise;
      }
  </code></pre>