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In the SPA mode, custom code works a little differently than non SPA mode. Since we never do full page reload in the SPA mode, page level custom code needs to ensure that it doesn’t interfere with other pages.

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TL;DR

  • Keep page specific code out of app level custom code.
  • Whenever possible, use plain HTML/CSS instead of Javascript.
  • Use <script type="module"> to avoid global name conflicts.
  • Instead of “DOMContentLoaded” in page level level custom code, wait for elements that you need using window.SOFTR_PAGE.waitFor .
  • Use window.SOFTR_PAGE.beforeUnload to cleanup elements and timers before navigating to a new page. This function can be called multiple times to register several cleanup functions.

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Keep page specific code out of app level custom code

Scripts in the App header/App footer custom code execute only once—on the first page load. They won’t re-execute when navigating between pages, unlike in non-SPA mode. To ensure your app looks consistent whether you’re navigating from another page or visiting directly via URL, keep page-specific code in custom code blocks on the page or in page-level custom code.

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Cleanup any dynamically inserted DOM nodes on page navigation

When navigating to a new page, HTML elements dynamically injected by JavaScript outside the custom code’s own scope won’t be automatically cleaned up. Use the window.SOFTR_PAGE.beforeUnload API to remove any dynamically rendered DOM nodes. This ensures that navigating from page A to page B doesn’t leave behind remnants from page A. Here’s an example 
<div id="my-container-for-page1">
   Any DOM node inserted inside the scope of this custom code block
   will be automatically removed on page navigation.
</div>

<script type="module">
  const dynamicElem = document.createElement("div")
  dynamicElem.innerHTML = `
     This element is injected directly into the body, which is preserved
     across navigations.
     This needs to be cleaned up on page navigation.
  `
  document.body.appendChild(dynamicElem)
  window.SOFTR_PAGE.beforeUnload(() => {
     // Will run just before navigating to a new page.
     dynamicElem.remove()
  })
  
  const anotherElement = document.createElement("div")
  anotherElement.innerHTML = `
     This element is inserted within an element owned by this custom
     code block.
     There's no need to clean this up manually :)
  `
  document.getElementById("my-container-for-page-1").appendChild(anotherElement)
</script>

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Cleanup timers and resize observers on page unload

If your page custom code sets up timers or resize observers, they need to be cleaned up before the page unloads. This ensures that the timers don’t keep running after navigating away from the page. For example, here’s a custom code block which shows the number of seconds this page has been open for 

The page has been open for <span id="page-timer-count">0</span> second(s)
<script type="module">
  let count = 0
  const interval = setInterval(() => {
    count++
    document.getElementById("page-timer-count").innerText = count;
  }, 1000)
  
  window.SOFTR_PAGE.beforeUnload(() => {
    clearInterval(interval)
  })
</script>

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Don’t use DOMContentLoaded in page level custom code

DOMContentLoaded will only fire once, on app load. Navigating between the pages will not re-run the event listener. Instead, window.SOFTR_PAGE.waitFor provides a simple way to wait for an element to be on the page before continuing. 
<script type="module">
   window.SOFTR_PAGE
     .waitFor(
       // Don't forget the `() =>`!
       () => document.getElementById("some-element-id"))
     .then(() => {
       const element = document.getElementById("some-element-id")
       // element is visible now
     })
</script>