How to use applyAsync() in javascript

Question

I am using javascript code to fetch items of some itemType, I see two method in aras - apply() and applyAsync(). 
 How do i use applyAsync()? An example of working code would be helpful. 
 
 Thanks 
 Vinay

Christopher Gillis · Answer

Hi Vinay, 
 I answered another forum post with a use case for applyAsync() that I wanted to share here. The users there were trying to display a spinner to let the users know that a long item query was running. The code in the Gist below uses applyAsync() to satisfy this use case by starting the spinner, doing an apply with applyAsync(), and then stopping the spinner after it returns. 
 https://gist.github.com/cgillis-aras/ea18abe9c0e94c6e858c544f5d9c077e 
 The difference between apply() and applyAsync() is that apply() halts the execution of your code until the query is completed at which point it will return an item containing the results of your query. applyAsync() on the other hand returns a Promise that can eventually handle the result of the query and does not halt your code. There's a number of different articles available online (like this one ) that explain Promises, asynchronous code, and the benefits of using them. 
 Chris 
 Christopher Gillis 
 Aras Labs Software Engineer