TypeScript Data Types

In TypeScript, the data types are useful to define a type of data the variable can hold such as number, string, boolean, etc. in our application. The TypeScript will support all the types that are supported by JavaScript.


As discussed, TypeScript is a strict type checking language so the compiler will associate the type to the variables at the time of variable initialization based on the value or defined type.

TypeScript Data Types Syntax

Following is the syntax of defining a type or data type to the variables in typescript.


[Keyword] [Variable Name]: [Data Type] = [Value];

[Keyword] [Variable Name]: [Data Type];

If you observe the above syntax, we added data type after the variable name to tell the compiler that the type of data the variable can hold or the type of variable that belongs to.


  • [Keyword] - It’s a keyword of the variable either var, let or const to define the scope and usage of variable.
  • [Variable Name] - Its name of the variable to hold the values in our application.
  • [Data Type] - It’s a type of data the variable can hold such as number, string, boolean, etc.
  • [Value] - Assigning a required value to the variable.

You need to remember that the data types part is optional while declaring and defining the variables in typescript. Now, we will learn how to use data types in TypeScript with examples.

TypeScript Data Types Example

Following is the example of defining the variables with required data types in typescript.


let uname: string = "Suresh Dasari"; // string

let ulocation: string = "Hyderabad"; // string

let age: number = 33; // number

let isCompleted: boolean = true; // boolean


console.log("Name:" + uname); // Suresh Dasari

console.log("Location:" + ulocation); // Hyderabad

console.log("Age:" + age); // 33

console.log("Is Completed:" + isCompleted); // true

If you observe the above TypeScript data types example, we defined multiple variables with different data types based on our requirements.

TypeScript Different Data Types

In typescript, different type of data types available, those are:


TypeData Types
Primitive / Built-in Types number, string, boolean, etc.
User-defined / Object Types array, tuple,enum, etc.

Following diagram will illustrate more details about different data types in typescript.


Different data types in typescript


If you observe the above diagram, the any type is pointing to the both primitive and user-defined types because it is a super set of all the data types.

TypeScript Primitive Data Types

Following table lists the different type of built-in or primitive data types in typescript.


number string boolean
void null undefined
never any  

TypeScript User-defined Data Types

Following table lists the different type of user-defined data types in typescript.


array class interface
tuple enum function

In the next typescript chapters, we will learn about each data type in-detail with examples.