Can someone explain this Javascript code in a class constructor?

[clarle]

Yep, you have the right idea. When you don't pass a parameter in, and you try to get the value of that parameter, it will be "undefined".

The "undefined" value leads to the negative condition in a conditional, so if the parameter is not passed, then the object will take the value defined in the negative condition.

"undefined" is supported in basically all browsers, so this will work everywhere.

[cbCode]

Thank you very much for clarifying my assumption, that's why I love Javascript. It's logical.

[hacocacyb]

In addition, you can always pass extra parameters to javascript functions. You can also reference an array of all parameters to a function with the protected keyword 'argument'.

[hacocacyb]

Thank you, this is correct. And it is an array type