Introduction to Variables
Variables are containers that store data values. In JavaScript, you can declare variables using var, let, or const keywords. Each has different characteristics and use cases.
Data Types in JavaScript
JavaScript has several primitive data types: string, number, boolean, undefined, null, symbol, and bigint. Understanding these types is crucial for effective programming.
Variable Declaration
1// Different ways to declare variables
2let userName = "Alice";
3const userAge = 25;
4var isActive = true;
5
6// Data types
7let message = "Hello World"; // string
8let count = 42; // number
9let isComplete = false; // boolean
10let data = null; // null
11let value; // undefinedThis example shows how to declare variables and different data types in JavaScript.
Best Practice
Always use const for values that won't change, and let for values that will change. Avoid using var in modern JavaScript.
Important Note
JavaScript is dynamically typed, meaning you don't need to specify the data type when declaring variables.
Comments (2)
Great explanation! This really helped me understand the differences between let and const.
Could you add more examples about when to use each variable type?