title: Do I need to add properties to make the desired output?
body: <p>I've got 1 of three of my desired outputs (the second test) but can't figure out how to get the other two. I've included test code below also.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>function car(gas, mpg) {
    this.gas = gas;
    if (this.gas &lt;= 0) {
      this.empty = true;
    }
    this.mpg = mpg;
    //this.range = gas * mpg;
    //this.empty = empty;
  
    this.drive = function(miles) {
      this.gas -= miles / this.mpg;
      if (this.gas &lt;= 0) {
        this.empty = true;
      }
    };
  
    this.fill = function(gallons) {
      if (this.gas &lt;= 0) {
        this.fill = false;
      }
    };
  }
  //test code
  
  var test = new car(15, 30);
  console.log(test.empty); //expected output = false
  
  test.drive(500);
  console.log(test.empty); //expected output = true
  
  test.fill(20);
  console.log(test.empty); //expected output = false</code></pre>
  </div>
  </div>
  </p>