TypeScript Number

Summary: in this tutorial, you’ll learn about the TypeScript number data types.

All numbers in TypeScript are either floating-point values or big integers. The floating-point numbers have the type number while the big integers get the type bigint.

The number type

The following shows how to declare a variable that holds a floating-point value:

let price: number;Code language: JavaScript (javascript)

Or you can initialize the price variable to a number:

let price = 9.95;Code language: JavaScript (javascript)

As in JavaScript, TypeScript supports the number literals for decimal, hexadecimal, binary, and octal literals:

Decimal numbers

The following shows some decimal numbers:

let counter: number = 0;
let x: number = 100, 
    y: number = 200;Code language: JavaScript (javascript)

Binary Numbers

The binary number uses a leading zero followed by a lowercase or uppercase letter “B” e.g., 0b or 0B :

let bin = 0b100;
let anotherBin: number = 0B010;Code language: JavaScript (javascript)

Note that the digit after 0b or 0B must be 0 or 1.

Octal Numbers

An octal number uses a leading zero followed by the letter o (since ES2015) 0o. The digits after 0o are numbers in the range 0 through 7:

let octal: number = 0o10;Code language: JavaScript (javascript)

Hexadecimal numbers

Hexadecimal numbers use a leading zero followed by a lowercase or uppercase letter X (0x or 0X). The digits after the 0x must be in the range (0123456789ABCDEF). For example:

let hexadecimal: number = 0XA;Code language: JavaScript (javascript)

JavaScript has the Number type (with the letter N in uppercase) that refers to the non-primitive boxed object. You should not use this Number type as much as possible in TypeScript.

Big Integers

The big integers represent the whole numbers larger than 2⁵³ – 1. A Big integer literal has the n character at the end of an integer literal like this:

let big: bigint = 9007199254740991n;Code language: JavaScript (javascript)

Summary

• All numbers in TypeScript are either floating-point values that get the number type or big integers that get the bigint type.
• Avoid using the Number type as much as possible.