JavaScript Data Types

JavaScript Data Types – Overview of JS Types

JavaScript has a variety of data types that are essential to understand, especially for beginners. Here’s an overview of the main data types in JavaScript:

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1. Primitive Data Types

Primitive data types are the most basic types of data. They include:

• String: Used for text. Strings are written inside quotes (" ", ' ', or backticks ` `).
  • Example: "Hello, World!"
• Number: Represents both integer and floating-point numbers.
  • Example: 42, 3.14
• Boolean: Represents a logical entity and can have two values: true or false.
  • Example: true, false
• Undefined: A variable that has been declared but not assigned a value.
  • Example:

    let x;
    console.log(x); // undefined
    

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• Null: Represents the intentional absence of any object value.
  • Example:

    let y = null;
    console.log(y); // null
    

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• Symbol: Represents a unique identifier.
  • Example:

    let sym = Symbol('description');
    

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• BigInt: Used for numbers larger than the Number type can safely handle.
  • Example:

    let bigIntNum = 1234567890123456789012345678901234567890n;
    

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2. Non-Primitive Data Types (Objects)

Objects are collections of properties and methods.

• Object: Used to store collections of data or more complex entities.
  • Example:

    let person = {
      firstName: "John",
      lastName: "Doe",
      age: 30
    };
    

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• Array: A special type of object used to store multiple values in a single variable.
  • Example:

    let fruits = ["Apple", "Banana", "Cherry"];
    

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• Function: A block of code designed to perform a particular task.
  • Example:

    function greet() {
      console.log("Hello, World!");
    }
    

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3. Special Objects

• Date: Represents date and time.
  • Example:

    let date = new Date();
    

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• RegExp: Represents regular expressions.
  • Example:

    let pattern = /codeformate/i;
    

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4. Type Checking

You can check the type of a variable using the typeof operator.

• Example:

  console.log(typeof "Hello"); // "string"
  console.log(typeof 42);      // "number"
  console.log(typeof true);    // "boolean"
  

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Understanding these basic data types and their usage is fundamental to writing and understanding JavaScript code.