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Blake Campbell
Blake Campbell

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Are Default Params in JavaScript bad? (Snack pack #4)

Not if it's still passed

Take this example:

I wrote this function well over two years ago. It just pops up a notification if the user makes a CRUD call. (Create, Read, Update Delete). The function only takes two defined parameters a message and a notification.

The notification parameter is a boolean.

notification = true // notify user by a pop-up
notification = false // inline-notification by form button, or in a defined space
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Looking back at this function, it could be much better.

  • Instead of a notification boolean, it can be notification style as a string.
  • Call with the second parameter everywhere

Back to the question: Default Params in JS bad?

I think so if I'm not explicitly calling with all the params of a function. It's okay to have a fallback, but don't depend on it!


  • It's leaves technical debt.
  • How is another developer supposed to know what parameters are passed if they only see a partial picture?
  • My boolean parameter is bad in this case.

How I refactored this function:

carbon (2)

My snack pack reads are intended for a quick read without any fluff or BS.

Feedback is always welcome.

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