After an upgrade, some fragments get broken because JS strict mode seems to be enforced now

Issue

• We do not declare JS variables when developing fragments. After an upgrade, these fragments stop working properly.

Environment

• Upgrades to the following Patch Releases: 2023.Q3.5+, 2023.Q4.1+
• Upgrades to 2024.Q1 or newer Quarterly Release

Resolution

• This is a consequence of using JavaScript modules in fragment scripts. Modules automatically enforce strict mode, preventing undeclared variables from being used.
  • This behavior was introduced by LPS-202182.
  • The previous code was relying on global variables creation which is a bad practice.
• The solution in this case would be to modify the code to declare all variables.
• However, a temporary workaround has been developed to give more time for this adoption:
  • A new setting (true by default) is available in Instance Settings > Page Fragments > Javascript > Javascript Module Enabled.
  • Unchecking that setting will make those fragments work again.
  • As mentioned before, be aware that this setting will be removed in future versions. Users will no longer have the option to disable type="module".
  • If you cannot see that setting, you may want to ask for a hotfix including LPD-33141.

Additional Information

• JavaScript modules
• Sloppy mode