TypeScript Numbers

Numbers are used to perform mathematical operation. All numbers are stored as floating point numbers. Number literals can form of binary, octal, decimal, hexadecimal and floating point values.

The binary number starts with 0b and consists of 0s and 1s. For example, 0b1100 is a binary representation and its decimal value is 12.

let value : number = 0b1100; // Binary literal    
// Display stored value
console.log(value); // 12

Observe that by default binary literals are stored in decimal format. In the case when the binary value needs to be displayed, we can use the toString() method.

let value : number = 0b1100; // Binary literal    

// Display stored value
console.log(value); // 12

// Display binary value
console.log(value.toString(2)); // 1100

Here the base 2 value is given in the toString() method. These 12 decimal values represent binary formats (1100).

Octal Number : A decimal number which is start with 0o it is called octal number.

let value : number = 0o12; // Octal literal   

// Display stored value
console.log(value); // 10

// Display Octal value
console.log(value.toString(8)); // 12

Decimal Number : is positive and negative numbers which contain digit of [0-9]. And large number can be separated by underscore.

let a : number = 123; 
let b : number = 99_9_99; 

// Display stored value
console.log(a); // 123
console.log(b); // 99999

Hexadecimal Number : This number are start with 0x. The suffix may contain numerals such as [0-9] and alphabet [A-F (A-F)] letters.

let value : number = 0x7b; // Hexadecimal literal 

// Display stored value
console.log(value); // 123

// Display Hexadecimal value
console.log(value.toString(16)); // 7b

Number Methods

toExponential()

let num : number = 102334234;
// Test
console.log(num.toExponential());
console.log(num.toExponential(3));
console.log(num.toExponential(2));
console.log(num.toExponential(1));

1.02334234e+8
1.023e+8
1.02e+8
1.0e+8

toFixed()

let num : number = 102.934234;
// Test
console.log(num.toFixed());
console.log(num.toFixed(3));
console.log(num.toFixed(2));
console.log(num.toFixed(1));

103
102.934
102.93
102.9

toLocaleString()

var num : number = 345.9875643;
// Test
console.log(num.toLocaleString());
console.log(num.toLocaleString('ja-JP'));
console.log(num.toLocaleString('de-AT'));
console.log(num.toLocaleString('tr-TR'));
console.log(num.toLocaleString('fr-FR'));

"34,434,555.988"
"34,434,555.988" 
"34 434 555,988" 
"34.434.555,988" 
"34 434 555,988"

toPrecision()

var num : number = 345.9875643;
// Test
console.log(num.toPrecision());
console.log(num.toPrecision(4));
console.log(num.toPrecision(3));
console.log(num.toPrecision(2));
console.log(num.toPrecision(1));

345.9875643
346.0
346
3.5e+2
3e+2

toString()

let num : number = 345.9875643;

let strNum : string = num.toString();
// Test
console.log(num,typeof num);
console.log(strNum,typeof strNum);

345.9875643 'number'
345.9875643 string

let num : number = 123;

// test
console.log(num.toString(2)); // Binary
console.log(num.toString(16)); // Hex number
console.log(num.toString(8)); // Octal
console.log(num.toString(4)); // Base 4

1111011
7b
173
1323

valueOf()

let num  = new Number(143);

// test
console.log(typeof num);   // number
console.log(num.valueOf()); // 143