Making a Value Persistent

Persisting the value

JavaScript supports function scope, which means that variables defined inside a function cannot be accessed from outside the function. As a result, each function has its own scope. If we invoke a function multiple times, there'll be multiple scopes. However, no matter how many times we invoke it, it wouldn't create a different output.

For our count value, we can visualize what happened with the two updates in two different scopes in the figure below.