Example of how to store an ajax request in ES6.

memoized-ajax-es6.js

/**
 * Demonstration of a stored ajax request in ES6.
 */
class ReadingList {
  // Initialize the instance with an empty variable just so we can null-check it.
  constructor () {
    this.article_list = null
  }

  // Use a getter for a slightly more concise syntax.
  get articles () {
    // Promises!
    return new Promise((resolve, reject) => {
      // if the article list is already populated, we're done. Resolve right away.
      if (this.article_list) {
        return resolve(this.article_list)
      }

      // Otherwise, make an ajax request and then resolve with the returned data.
      $.get('/user/123456/articles').done((data) => {
        this.article_list = data
        resolve(this.article_list)
      })
    })
  }
}

// Create a new instance.
const my_reading_list = new ReadingList()

// get the articles and do something with them
my_reading_list.articles.then((articles) => {
  const markup = render_template(template, articles)
  document.body.insertAdjacentHTML(markup)
})

This is clearly not the best way to write this code. I'd love some feedback on structure.