title: How can I get the JSON of an article from the API when I just know the node_slug?
body: <p>I have a list of node_slug values of Khan Academy articles like:</p>
  
  <ul>
  <li><code>a/square-roots-of-perfect-squares-art</code></li>
  <li><code>a/number-of-solutions-to-a-system-of-equations</code></li>
  <li><code>a/distance-formula</code></li>
  </ul>
  
  <p>Unfortunately, as far as I know, there is no way from this piece of data to get the API JSON. For that, you need an id like "xe504dd90". This is different from <code>exercises</code> and <code>videos</code>, which both have a dedicated API. </p>
  
  <p>What it's possible is to get the page from the main website, which has all the data I need and much more, but it's more difficult to parse. What I need are the main metadata of the page (title, author, image_url, etc.). </p>