Answers for "let vs var vs const in js"

26

var vs let vs const

var: 
	- hoisted (always declared at top of scope, global if none)
    - function scope
let:
    - block scope
    - not redeclarable
const: 
    - block scope
    - not reassignable
    - not redeclarable
    
Note: Although it may seem like these hold only semantic meaning, using the
appropriate keywords helps the JS engines' compiler to decide on what to optimize.
Posted by: Guest on May-11-2021
2

js var vs const

//var variables can be re-declared and updated
    var greeter = "hey hi";
    var greeter = "say Hello instead";
//it becomes a problem when you do not realize that a variable 
//greeter has already been defined before.

//const declarations are block scoped
//const cannot be updated or re-declared
	const greeting = "say Hi";
	greeting = "say Hello instead";// error: Assignment to constant variable. 

	const greeting = "say Hi";
	const greeting = "say Hello instead";// error: Identifier 'greeting' has already been declared
Posted by: Guest on August-01-2021

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