title: An object attribut is undefined?
body: <pre><code>var obj = {
      name:'ian',
      getName(){
          console.log(`inside:${this.name}`)
      }
  }
  
  obj.getName()
  obj.getName.call({name:'oliver'})
  var fn = obj.getName.call({name:'sullivan'})
  </code></pre>
  
  <p>console.log is ian olive and sullivan,but i don't get it ,why?i didn't console fn ,why it can be output 'sullivan'?and if i do this:</p>
  
  <pre><code>var obj = {
      name:'ian',
      getName(){
          console.log(`inside:${this.name}`)
      }
  }
  
  obj.getName()
  obj.getName.call({name:'oliver'})
  var fn = obj.getName.call({name:'sullivan'})
  console.log(fn)
  </code></pre>
  
  <p>it will be console ian oliver sullivan and [<strong>undefined</strong>]
  why??need help :) please</p>