Breaks JS scripts on node edit forms

Hello Paul,

Can I ask which version of the metatag module u have and could you try updating it?
Not sure if it would be the problem to your issues but I know many problems arise when the module version is too low.

confirming identical behavior for us

Confirming I am an ass. :)

This is a caching error on our end. Worked in dev but our cdns where sitting on old js files making it not work on our live setup which has CDNs

That said this function in yoast_seo.js did cause a fatal error and break CKEditor until I add the null check.

/**
 * Parses the input in snippet preview fields on input evt to data in the metatag and path fields
 * @param source
 * @param target
 */
YoastSEO_DrupalSource.prototype.parseSnippetData = function(source, target) {
  var listener = function ( ev ) {
    // textContent support for FF and if both innerText and textContent are
    // undefined we use an empty string.
    document.getElementById(target).value = (ev.target.value || "");
    this.triggerEvent(target);
  }.bind(this);
  if(document.getElementById(source)) { // added this
    document.getElementById(source).addEventListener("blur", listener);
  } //added this
};

Hope this helps you @MrPaulDriver

The JS problem should have been fixed by #2784549: Views Improvements.

The JS problem is still present in both 7.x-1.0 and 7.x-1.x-dev. The quickfix proposed in #5 fixes the problem. Is it a correct solution though or should the caller function check the source exists before calling parseSnippetData?

I can confirm we were still getting the JS issue, causing CKeditor to not show. This was even with the latest or dev version.
The patch mentioned in #5 worked in fixing it.

Attached is a patch file, just implementing the basic change suggested in #5.

Tidied up the code a little bit, can you verify the change to the if() statement still works?

Unfortunately that doesn't work for me.

typeof document.getElementById(source) is returning 'object' in my case.
document.getElementById(source) is returning 'null'

This works:
if (document.getElementById(source) != null) {}

So more like this?

Yep that works fine for me :)

Looks good, committed. Thanks!