Adding multiple copies of the same JavaScript settings to a page will result in them being added multiple times (once for each time that they are added). This can cause a variety of issues such as, in the case of adding multiple WYSIWYG editors to one page which all use the same settings, broken toolbar buttons.
There is currently no way to add JavaScript settings to a page in Drupal 7 and guarantee that they are idempotent. This was made possible in Drupal 8+ with Adding JS settings is now idempotent (JS settings merging behavior modified) → .
Workaround, such as using a static variable and tracking if the settings have been added before, all have a variety of issues.
Backdrop addressed the issue by added the ability to specify a key when adding JavaScript settings if you want to ensure that a group of settings is only added to a page once.
This blocks the release of the Editor → module.
You can recreate this with the Editor module by adding a text editor to a text format and then displaying multiple fields with that format on one page. The text editor's toolbar buttons will appear multiple times; once for each of the fields on the page with the format.
Add the ability to specify a key when adding JavaScript settings which ensures that a group of settings is only added to a page once.
Needs review
7.0 ⚰️
A port of the linked PR that allows a key to be specified when adding JS settings which ensures that they are only added to the page once.