30-seconds-of-code/glossary/Value-vs-reference.md

Value vs reference

When passing a variable by value, a copy of the variable is made, meaning that any changes made to the contents of the variable will not be reflected in the original variable. When passing a variable by reference, the memory address of the actual variable is passed to the function or variable, meaning that modifying the variable's contents will be reflected in the original variable. In JavaScript primitive data types are passed by value while objects are passed by reference.