What Is the Scope of Variables in Javascript?
Do They Have the Same Scope Inside as Opposed to Outside a Function? or Does It Even Matter? Also, Where Are the Variables Stored If They Are Defined Globally?...
What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?
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TLDR
JavaScript has lexical (also called static) scoping and closures. This means you can tell the scope of an identifier by looking at the source code.
The four scopes are:
- Global - visible by everything
- Function - visible within a function (and its sub-functions and blocks)
- Block - visible within a block (and its sub-blocks)
- Module - visible within a module
Outside of the special cases of global and module scope, variables are declared using var (function scope), let (block scope), and const (block scope). Most other forms of identifier declaration have block scope in strict mode.
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