In Your Own Words

gistfile1.txt

What is scope?

Variable Scope
	-Defines how a declared variable can or can not be accessed at different points in the code

	-Global variable is accessible everywhere in the code, and is declared outside of a function.

	-Block scope refers to how a variable is defined within a function and is only accessible within its function’s instructions.

	-Global = outside a function;
	Block = inside a function

	***Global variable is untouched when Block variable is used/declared

	-Scope chain is when JS looks inside a function to determine the value of a declared variable. If it’s not there, it will continue looking up the chain to determine to value of claimed variable. **side effects are not inherently a “bad thing.”

Why are global variables avoided? & What are side effects, and what is a pure function?
	-Tend to cause unintended side effects: when a function reaches outside of local scope and further up into a parent scope to define a value.
	-Global variables + unintended side effects = indeterminate code
	-Determinate function: one that will always return same value
	-Indeterminate function: returns different values; leads to buggy code
	-Pure function: determinate w/ no side effects

Explain JavaScript’s strict mode.

	-will raise an error if a variable is declared without a ‘let’ or ‘const’
	-‘use strict’; command at tope of code enforces strict mode for whole file, or at the top of a function to only apply it w/in a function
	-best practice to use it at top of all JS files

	-EXCEPTION to using global variables: when using JS library, like jQuery, jQuery applies $ global variable, and can be referenced in JS file.