title: JS - chain async methods in sequence w/o callback or modification
body: <p>I'm trying to add a "default callback" to a prototype that will assign a callback function (in the form of a promise) to an async method if none is provided.</p>
  
  <p>The goal is to have a class's chain of async methods run synchronously</p>
  
  <pre><code>Item.async1().async2()....asyncN()
  </code></pre>
  
  <p>Mind you, the async functions themselves expect a callback but they're not passed as arguments in the function call (which tells me that the class needs a default behavior when the callback lookup fails)</p>
  
  <p>Spec states that I cannot directly modify the behavior or side effects of the prototype methods. I can add prototype methods. We have no visibility into how these prototype methods are implemented.</p>
  
  <p>TLDR: Without modifying the prototype methods, how can you chain an N number of async methods and ensure they run sequentially?</p>
  
  <p>BTW: Promisifying the prototype methods in question would be helpful if I wanted to implement the promisified versions, but it looks like we're constrained to the original function calls</p>