There are actually two main ways to declare variables in modern JavaScript: let
and const
. Both are block-scoped, meaning their scope is limited to the block of code they are declared in (like an if statement or a function).
Using let
allows you to reassign a value to the variable later in your code. This is useful for variables that will change throughout your program.
On the other hand,const
is used for variables that should hold a constant value and not be reassigned. This helps prevent accidental modification and improves code readability.
Here’s an example:
let name = "Alice"; // Declares a variable with let and assigns the value "Alice"
name = "Bob"; // Reassigns the value of name to "Bob"
const PI = 3.14159; // Declares a constant with const and assigns the value of pi
// PI = 3; This would cause an error because PI is constan
Generally, it’s recommended to use const by default and only use let when you specifically need to reassign the variable. This helps prevent bugs and makes your code more predictable.