rjwilliams87/scope

## scope
What is scope?
  Scope defines how the variables declared in a program can be accessed at different places in the code. Any variable
  declared outside of a function has a globlal scope. Variables declared within the function block have block scope. If a variable
  has global scope it is accessible throughout the code by any function. Global variables may lead to unexpected side effects
  making functions indeterminate, thus it is best to avoid using them. Variables with block scope are accessible only within the function
  block in which they are defined, and thus have no effects on variables outside of their scope.

Why are global variables avoided?
  Global variables can lead to unintended side effects and indeterminate functions. JavaScript uses the scope chain to find the value of
  a variable once it is called inside of a function. If the variable is not defined within the function it will reach to the global level
  to find the value of the variable. If the function calls for the variable to be altered, it will be done so globally. Altering gloabal
  variables can lead to collision with other parts of the code that rely on the same global variable.

  It is best practice to keep a function pure and determinate. This is not possible when functions must rely on global variables. It is
  best to avoid using them, because they can lead to hard-to-track-down bugs in the code.

Explain JavaScript's strict mode.
  JavaScript uses the strict mode to catch common coding errors when writing the code. By using strict mode JavaScript will disable certain
  features and throw an error in cases when variables are improperly declared. Strict mode prevents the programmer from accidentally
  creating global variables, and thus makes code more secure.

What are side effects, and what is a pure function?
  A side effect is when a function reaches out of its local scope into the global scope and alters variable(s) globally. This causes
  unintended effects on the program as a whole, since other code within the program may rely on the same variable. This leads to functions
  that are indeterminate. By declaring variables in the function block, functions are kept pure. That is to say, that is to say that it
  has no side effects and is determinate, meaning that given the same inputs at various places within the code it will always return the
  same thing.
	What is scope?
	Scope defines how the variables declared in a program can be accessed at different places in the code. Any variable
	declared outside of a function has a globlal scope. Variables declared within the function block have block scope. If a variable
	has global scope it is accessible throughout the code by any function. Global variables may lead to unexpected side effects
	making functions indeterminate, thus it is best to avoid using them. Variables with block scope are accessible only within the function
	block in which they are defined, and thus have no effects on variables outside of their scope.

	Why are global variables avoided?
	Global variables can lead to unintended side effects and indeterminate functions. JavaScript uses the scope chain to find the value of
	a variable once it is called inside of a function. If the variable is not defined within the function it will reach to the global level
	to find the value of the variable. If the function calls for the variable to be altered, it will be done so globally. Altering gloabal
	variables can lead to collision with other parts of the code that rely on the same global variable.

	It is best practice to keep a function pure and determinate. This is not possible when functions must rely on global variables. It is
	best to avoid using them, because they can lead to hard-to-track-down bugs in the code.

	Explain JavaScript's strict mode.
	JavaScript uses the strict mode to catch common coding errors when writing the code. By using strict mode JavaScript will disable certain
	features and throw an error in cases when variables are improperly declared. Strict mode prevents the programmer from accidentally
	creating global variables, and thus makes code more secure.

	What are side effects, and what is a pure function?
	A side effect is when a function reaches out of its local scope into the global scope and alters variable(s) globally. This causes
	unintended effects on the program as a whole, since other code within the program may rely on the same variable. This leads to functions
	that are indeterminate. By declaring variables in the function block, functions are kept pure. That is to say, that is to say that it
	has no side effects and is determinate, meaning that given the same inputs at various places within the code it will always return the
	same thing.