JavaScript Data Types Explained: Primitive vs Non-Primitive Data Types

JavaScript Data Types: Primitive and Non-Primitive Data Types Data types are an important concept in JavaScript because they define the kind of value a variable can store. Understanding data types helps developers write reliable and efficient code. What is a Data Type? A data type defines what kind of value a variable can hold. Example let name = " John " ; // String let age = 25 ; // Number let isActive = true ; // Boolean In the above example, each variable stores a different type of value. Types of Data Types in JavaScript JavaScript data types are broadly classified into two categories: Primitive Data Types Non-Primitive Data Types Primitive Data Types Primitive data types store a single and simple value. Characteristics Store a single value. Immutable (cannot be changed directly). Compared by value. Stored directly in memory. Types of Primitive Data Types 1. String Used to store textual data. let name = " John " ; 2. Number Used to store numeric values. let age = 25 ; let price = 99.99 ; 3. Boolean Represents either true or false . let isLoggedIn = true ; 4. Undefined A variable that has been declared but not assigned a value. let city ; console . log ( city ); // undefined 5. Null Represents the intentional absence of a value. let user = null ; 6. Symbol Used to create unique identifiers. let id = Symbol ( " id " ); 7. BigInt Used to store very large integers beyond the safe Number limit. let largeNumber = 123456789012345678901234567890 n ; Non-Primitive Data Types Non-primitive data types store multiple values or complex data structures. Characteristics Can store collections of data. Mutable (their contents can be modified). Compared by reference. Stored as references in memory. Types of Non-Primitive Data Types 1. Array Used to store multiple values in a single variable. let colors = [ " red " , " green " , " blue " ]; 2. Object Used to store data as key-value pairs. let person = { name : " John " , age : 25 }; 3. Function Functions are reusable blocks of co