JavaScript Variables and Data Types Explained
Variables and data types are the building blocks of JavaScript. They allow you to store, manage, and manipulate information in your code. Understanding them is essential for writing effective scripts.
πΉ JavaScript Variables
Variables are containers for storing data values.
- Declaring Variables:
- var β older way, function-scoped.
- let β modern way, block-scoped.
- const β for values that donβt change.
Example:
let name = "Alice";
const age = 25;
var city = "New York";
πΉ JavaScript Data Types
JavaScript has several data types:
- String β Text values.
let greeting = "Hello World";
- Number β Numeric values (integers and decimals).
let score = 100;
- Boolean β True or false values.
let isActive = true;
- Null β Represents an empty or unknown value.
let data = null;
- Undefined β A variable declared but not assigned a value.
let result;
- Object β Collections of key-value pairs.
let person = { name: "Alice", age: 25 };
- Array β Ordered lists of values.
let colors = ["red", "green", "blue"];
πΉ Best Practices
- Use let and const instead of var for cleaner code.
- Choose descriptive variable names.
- Initialize variables to avoid undefined.
- Understand data types to prevent errors in calculations or logic.
By mastering variables and data types, youβll gain the foundation needed to build more complex JavaScript programs.
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