TypeScript Number

 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 of 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 cost: number;

Or you can initialize the cost variable to a number:

let cost = 8.85;

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

Decimal numbers

The following shows some decimal numbers:

let index: number = 0;
let a: number = 100, 
    b: number = 200;

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;

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;

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

Octal Numbers

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

let octal: number = 0o10;

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;

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.

Conclusion

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