title: use of OR in javascript object in my case confusion
body: <p><img src="https://i.stack.imgur.com/Mznxq.png" alt="enter image description here"></p>
  
  <h1>Question 1</h1>
  
  <p>What does <code>options.left = options.left || _KSM.drawOption.left</code> means? I know <code>_KSM.drawOption</code> is referring to the object (also a function), but how does the <code>||</code> operator work here? Does it mean if <code>_KMS.drawOption.left</code> is undefinded, assign <code>options.left</code> to <code>options.left</code>?</p>
  
  <h1>Question 2</h1>
  
  <p>Why the author didn't use <code>this</code> keyword in this case? I assume it's because in this demo he didn't create an instance, because he just do the calling once. Rigtht? (I've seen a lots of <code>this</code> in jquery plugin that's why I'm consufed when the author call the function name instead of this within a function)</p>