var: Variables declared
varhave function scope, meaning they are accessible within the function they are declared in. If a variable is declared
varoutside of a function, it has a global scope and can be accessed anywhere in the code.
vardeclarations are hoisted, which means they are moved to the top of their scope and can be used before they are declared.
let: Variables declared
lethave block scope, meaning they are only accessible within the block they are declared in. This makes
leta better choice for local variables within loops or other control structures.
letdeclarations are also hoisted but cannot be accessed before they are declared.
const: Variables declared with
consthave block scope, just like
let. The critical difference is that
constvariables cannot be reassigned after they are displayed. This makes
consta good choice for declaring values that should not change, such as constant mathematical values or configuration settings.
In general, it is recommended to use
const by default and only use
let when you need to reassign the value of a variable.
var should be used sparingly, as the behavior of function scope and hoisting can lead to unexpected results.
Thanks for reading :)