JavaScript has primitive and composite data types.

Primitive Data Types

• Boolean: Represents logical values of true or false.

• Null: Denotes the lack of a value.

• Undefined: Indicates a variable that has been declared but has not been assigned a value.

• Number: Represents numeric values, including integers and floats.

• BigInt: Allows for representation of integers with arbitrary precision.

• String: Encapsulates sequences of characters.

• Symbol (ES6): Provides a unique, immutable value.

Composite Data Types

• Object: Represents a set of key-value pairs and is used for more complex data structures.
• Function: A callable object that can be defined using regular function syntax or using the new Function() constructor (rarely used).

Notable Characteristics

• JavaScript is dynamically-typed, meaning the data type of a variable can change during the execution of a program.
• Data type coercion can occur, where values are implicitly converted from one type to another in specific contexts, such as during comparisons.
• Arithmetic operations, particularly when one of the operands is a string, can lead to implicit type conversions.