What are JavaScript Data Types

JavaScript has several built-in data types that are used to represent different kinds of values. Here are the main data types in JavaScript:

  1. Primitive Data Types:
    • Undefined: Represents an uninitialized variable or a function without a return value.
    • Null: Represents the intentional absence of any object value.
    • Boolean: Represents a logical entity and can have two values: true or false.
    • Number: Represents numeric values, including integers and floating-point numbers.
    • String: Represents sequences of characters enclosed in single (' ') or double (" ") quotes.
  2. Object Data Type:
    • Object: Represents a collection of key-value pairs. Objects can be created using the Object constructor or object literal notation {}.
  3. Composite Data Types:
    • Array: Represents an ordered collection of values. Arrays can hold values of different data types.
    • Function: Functions are a special type of object in JavaScript. They can be defined using the function keyword.
  4. Special Data Types:
    • Symbol: Introduced in ECMAScript 6 (ES6), symbols are unique and immutable primitive values, often used as keys for object properties.

JavaScript is a dynamically typed language, meaning you don't need to specify the data type of a variable explicitly; the interpreter determines the data type at runtime. Additionally, JavaScript is loosely typed, allowing for flexible type conversions.

Here's a simple example that demonstrates some of these data types:

        
            let myUndefinedVar; // undefined
            let myNullVar = null; // null
            let myBooleanVar = true; // boolean
            let myNumberVar = 42; // number
            let myStringVar = "Hello, World!"; // string
            
            let myObjectVar = { key: "value" }; // object
            let myArrayVar = [1, 2, 3, "four", true]; // array
            
            function myFunction() {
              return "I am a function!";
            }            
        
    

In this example, variables are declared with different data types, including undefined, null, boolean, number, string, object, array, and function.

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