No, thats not correct. Value and reference assignment behave the same way for = (well, reference is hiding the fact that it’s not the literal string/object but a reference to it, a number is just the number).

Where it matters is in passing arguments to a function call. If you pass 42, it’s not mutable so incrementing, or doing anything, will not modify the original variable you passed-in. For a reference, using = will assign a new value (not change the original) but modifying the referenced object like, say a.b = 5 WILL change the original object.

It’s not really “pass by reference” that a C/C++ developer would understand but it seems to be the term that has stuck.

Sorry to get a bit nerdy here, but in JS, neither pass by value nor pass by reference make sense as it’s not defined by the spec and much less followed by the implementations. Strings can be pointers to buffers or ropes, numbers can be values (NaN-boxed or otherwise) or pointers depending on a number of conditions, it all depends. However, from what’s observable in the language, all variables are pass by value. There’s no way to pass anything at all by reference, primitive or not, i.e. you can modify a field of an object you were passed but you can’t change the object.

Hashtable of all strings made in program.