How to conditionally render HTML with Scala and the Lift Framework

You have a piece of HTML like the following

<!DOCTYPE html>
<html>
<head>
  <meta charset=utf-8 />
  <title>Your Snippet</title>
</head>
<body data-lift="ConditionalRendering">
  <div id="content-container">
    <span class="subtitle">Inclusions</span>
    <div class="info">
      <ul id="inclusions">
        <li class="inclusions-text">Guided tour</li>
      </ul>
    </div>
  </div>
</body>
</html>

and you want to hide the entire container if some condition is true.
Otherwise you want to display something inside the container.
Maybe populating an unordered list.

class ConditionalRendering{
  def render: (NodeSeq) => NodeSeq = {
    "#content-container" #> {if(trueness) PassThru else ClearNodes} andThen
    "#inclusions" #> {".inclusions-text *" #> { List("food", "drinks") } }                     
  }
}

The key part is andThen because if you use the & chaining method, the CSS selectors are applied to the original template, no matter what other selectors you are using.
In contrast, with andThen you are composing two functions with the first being executed before the second.

Keep Learning.
Until next time emoji-sunglasses

Riccardo Sirigu

Feb 01, 2017

How to conditionally render HTML with Scala and the Lift Framework