title: How do you write this if/else statement for a boolean checker
body: <p>I have these variables </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>    let isactive
      let istradeable = true
      let issellable = false
      let isrevocable
      let isburnable</code></pre>
  </div>
  </div>
  </p>
  
  <p>I have an if/else that basically look at these variables and checks if they are NOT null and if it's not assign it's value to a new variable. If it is NULL set variable to true</p>
  
  <pre><code>        if (isactive == null) {
          isactive = true
      } else {
          this.isactive = isactive
      }
      if (istradeable == null) {
          istradeable = true
      } else {
          this.istradeable = istradeable
      }
      if (issellable == null) {
          issellable = true
      } else {
          this.issellable = issellable
      }
      if (isrevocable == null) {
          isrevocable = true
      } else {
          this.isrevocable = isrevocable
      }
      if (isburnable == null) {
          isburnable = true
      } else {
          this.isburnable = isburnable
      }
  </code></pre>
  
  <p>This works but I'm looking for a simple function or maybe a better if/else statement that does the same thing. Thanks guys!</p>