ukhlivanov/Scope and Variables - Questions and answers

## Scope and Variables - Questions and answers
What is scope? Your explanation should include the idea of global vs. local scope.
Scope refers to the visibility of variables.  Global variable will be avialable everywhere in program. The local variable will only be available in the code block where it was defined (for example: class or function). When you define a variable in a function that has the same name as a variable in the global scope, the local variable will take precedence over the global one.

Why are global variables avoided?
Global variables are hard to use together with other developers. A global variable can be changed to any part of the program and therefore it is difficult to control it especially in a large application.

Explain JavaScript's strict mode.
When strict mode is enabled all variables should be declared(for example let myVar="myVar"), for variables without declaration error will be triggered. The command "use strict" can be put at the top of file to enforce strict mode, or at the top of functionб, in this case, strict mode will only work for function. Best practice is using strict mode as a default mode.

What are side effects, and what is a pure function?
A function is said to be pure when it is both determinate and has no side effects.
A side effect is when a function reaches outside its local scope up into a parent scope and alters a value that lives there.
	What is scope? Your explanation should include the idea of global vs. local scope.
	Scope refers to the visibility of variables. Global variable will be avialable everywhere in program. The local variable will only be available in the code block where it was defined (for example: class or function). When you define a variable in a function that has the same name as a variable in the global scope, the local variable will take precedence over the global one.

	Why are global variables avoided?
	Global variables are hard to use together with other developers. A global variable can be changed to any part of the program and therefore it is difficult to control it especially in a large application.

	Explain JavaScript's strict mode.
	When strict mode is enabled all variables should be declared(for example let myVar="myVar"), for variables without declaration error will be triggered. The command "use strict" can be put at the top of file to enforce strict mode, or at the top of functionб, in this case, strict mode will only work for function. Best practice is using strict mode as a default mode.

	What are side effects, and what is a pure function?
	A function is said to be pure when it is both determinate and has no side effects.
	A side effect is when a function reaches outside its local scope up into a parent scope and alters a value that lives there.