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Prompt:
1. What is scope? Your explanation should include the idea of global vs. block scope.
2. Why are global variables avoided?
3. Explain JavaScript's strict mode
4. What are side effects, and what is a pure function?

Scope has many valuable purposes and is widely used. Scope allows you to set different rules to specify when and how your code
can access a variable. Two types of scope are Block and Global. Block scope is set between specific functions and only effects
code inside that function. Global variables are avoided because it allows your code to be bug prone, and harder for multiple
contributors to work on it. Global variables can cause your code to become indeterminate. Meaning that it can return different
values. These values can sometimes not be intended, and make it difficult to track bugs. Block scopes allow us to define only
within the parameters we set. This is an example of a side effect.

Side effects occur when a function goes outside the local scope and into the parent scope, which can
cause the code to become indeterminate as mentioned earlier. A function that is determinate (meaning it's a function that always
returns the same value provided the same inputs) and that also has no side effects is called a pure function. Strict mode acts
as a security when writing code and avoiding pitfalls. Strict mode will trigger an error code when you do not use
let or const when defining a variable. Like "<html lang="en">" at the top of a code, we can use 'use strict' ; at the top of our
Javascript code to enforce it.