Variables are the heart of any programming language. In JavaScript, there are multiple ways available to declare a variable using different keywords like let, const, and var.
- var: Before ES6 or ES2015, it was the only way to declare variables in JavaScript. It declares variables in the global scope.
- let: It was introduced in ES6, It is used to declare variables in block scope.
- const: It was also introduced in ES6 to declare the constant variable whose values are not going to change throughout the code.
Example: The below code shows how you can declare variables using these keywords.
Javascript
var name = "GeeksforGeeks" ;
console.log(name); var name = "Virat Kohli" ; // Allowed
console.log(name); let desc = "A Computer Science Portal." ;
// let desc = "26000 International Runs."; // Not Allowed, // Error: Identifier 'desc' has already been declared console.log(desc); const workForce = 200; console.log(workForce); // const workForce; // Not Allowed, // Error: Missing initializer in const declaration |
Output
GeeksforGeeks Virat Kohli A Computer Science Portal. 200