Data Types

Learn what data types are and how JavaScript stores different kinds of values.

What is a Data Type?

A data type tells us what kind of value is being used in a JavaScript program.

For example, a student name is text, marks are numbers, and a result status can be true or false.

JavaScript data types classification.

JavaScript Data Types

JavaScript has eight standard data types: seven primitive types and one Object type.

Primitive Data Types

Example 1: Common Data Types

Here we create different variables and store different types of values.

const studentName = "Neha";
const marks = 90;
const isEnrolled = true;

console.log("Welcome to CIIT Training Institute ❤️🧑‍🎓.....!");
console.log("Student:", studentName);
console.log("Marks:", marks);
console.log("Enrolled:", isEnrolled);

Output

Checking Data Type with typeof

The typeof operator is used to check the type of a value.

Example 2: typeof Operator

const student = "Rohit";
const score = 85;
const selected = true;

console.log("Student:", student);
console.log("Type:", typeof student);

console.log("Score:", score);
console.log("Type:", typeof score);

console.log("Selected:", selected);
console.log("Type:", typeof selected);

console.log("CIIT Training Institute ❤️.....!");

Output

undefined and null

undefined usually means that a value has not been assigned, while null is commonly used to represent an intentional empty value.

Example 3: undefined and null

let course;
const trainer = null;

console.log("Course:", course);
console.log("Course Type:", typeof course);

console.log("Trainer:", trainer);
console.log("Trainer Type:", typeof trainer);

console.log("Learning at CIIT Training Institute ❤️🧑‍🎓.....!");

Output