According to google datatype is a particular kind of data item, as defined by the values it can take, the programming language used, or the operations that can be performed on it.
A data type, in programming, is a classification or categorization of data that specifies the type of values that a variable or expression can take on in a computer program. It tells the computer how to interpret the data and how to operate it.
In JavaScript, data types can be categorized into two main categories: Primitive types and Non-Primitive(object types).
Primitive Types: In programming refer to data types that are not objects and have no methods or properties of their own and refer to a single value. In JavaScript, there are six primitive types:
Number: used to represent numeric values, both integers and floating-point numbers. For example, 1, 2.5, -10, etc.
String: used to represent textual data as a sequence of characters. For example, "hello", "world", "123", etc.
Boolean: used to represent logical values of true or false. For example, true or false.
Undefined: used to represent a variable that has been declared but has not been assigned a value. For example, let a;
Null: used to represent a deliberate non-value or absence of an object. For example, let a = null;
Symbol: introduced in ECMAScript 6, used to create unique identifiers for object properties. For example, let a = Symbol('my symbol');
Non-Primitive Types(Object Types): also referred to as object types, they are complex data types that can store multiple values and have methods and properties. Here are some examples of non-primitive types in JavaScript:
Object: a collection of key-value pairs, where each value can be of any data type.
Array: a special type of object used to store ordered collections of data.
Function: a type of object that can be invoked with arguments to perform a specific task.
Date: used to represent dates and times.
RegExp: used to represent regular expressions for pattern matching.
Error: used to represent errors that can occur during program execution.
Difference between Primitive Types and Non-primitive types:
| Feature | Primitive Types | Non-primitive Types |
| Stored as | Actual Value | Reference to value |
| Type of value | Simple | Complex |
| Examples | Number, String, Boolean, null, undefined | Object, Array, Function |
| Comparison | Value equality using == and === operators | Reference equality using == and === operators |
| Mutation | Immutable; that is, they cannot be altered. | Mutable data types because we can change the value after creation. |
| Pass-by-value | Yes | No (pass-by-reference) |
| Size in memory | Fixed (usually 8 bytes) | Variable (depending on the size of the object and its properties) |
| Copy behavior | Creates a new copy of the value when assigned to a new variable or passed as an argument to a function | Creates a new reference to the same object when assigned to a new variable or passed as an argument to a function |
Keep in mind that the exact behavior of these data types may vary depending on the programming language or environment being used.
Understanding data types is essential for effective programming. By mastering the characteristics and behaviors of different data types, you can write more efficient, robust, and maintainable code, and avoid common pitfalls and errors.