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All About Numbers in JavaScript

Numbers are used to represent numerical values. They are written with or without decimals.

index.js
let x = 3.14;
let y = 3;

Number Properties​

JavaScript has only one type of number. Numbers can be written with or without decimals.

index.js
let x = 3.14;    // A number with decimals
let y = 3;       // A number without decimals

Number Methods​

JavaScript has a number of built-in methods for working with numbers.

toString()​

The toString() method returns a number as a string.

index.js
let x = 123;
console.log(x.toString()); // "123"

toFixed()​

The toFixed() method formats a number with a specific number of digits after the decimal point.

index.js
let x = 9.656;
console.log(x.toFixed(0)); // 10
console.log(x.toFixed(2)); // 9.66
console.log(x.toFixed(4)); // 9.6560

toPrecision()​

The toPrecision() method formats a number to a specified length.

index.js
let x = 9.656;
console.log(x.toPrecision()); // 9.656
console.log(x.toPrecision(2)); // 9.7
console.log(x.toPrecision(4)); // 9.656
console.log(x.toPrecision(6)); // 9.65600

valueOf()​

The valueOf() method returns the primitive value of a number.

index.js
let x = 123;
console.log(x.valueOf()); // 123

parseInt()​

The parseInt() method parses a string and returns an integer.

index.js
let x = "10";
console.log(parseInt(x)); // 10

parseFloat()​

The parseFloat() method parses a string and returns a floating point number.

index.js
let x = "10.33";
console.log(parseFloat(x)); // 10.33

isNaN()​

The isNaN() method returns true if the value is NaN, and false otherwise.

index.js
let x = NaN;
console.log(isNaN(x)); // true

isFinite()​

The isFinite() method returns true if the value is a finite number, and false otherwise.

index.js
let x = 10 / 0;
console.log(isFinite(x)); // false

Number()​

The Number() method returns a number, converted from its argument.

index.js
let x = true;
console.log(Number(x)); // 1

MAX_VALUE​

The MAX_VALUE property returns the largest number possible in JavaScript.

index.js
console.log(Number.MAX_VALUE); // 1.7976931348623157e+308

MIN_VALUE​

The MIN_VALUE property returns the smallest number possible in JavaScript.

index.js
console.log(Number.MIN_VALUE); // 5e-324

POSITIVE_INFINITY​

The POSITIVE_INFINITY property represents positive infinity.

index.js
console.log(Number.POSITIVE_INFINITY); // Infinity

NEGATIVE_INFINITY​

The NEGATIVE_INFINITY property represents negative infinity.

index.js
console.log(Number.NEGATIVE_INFINITY); // -Infinity

EPSILON​

The EPSILON property represents the difference between 1 and the smallest floating point number greater than 1.

index.js
console.log(Number.EPSILON); // 2.220446049250313e-16

MIN_SAFE_INTEGER​

The MIN_SAFE_INTEGER property returns the minimum safe integer in JavaScript.

index.js
console.log(Number.MIN_SAFE_INTEGER); // -9007199254740991

MAX_SAFE_INTEGER​

The MAX_SAFE_INTEGER property returns the maximum safe integer in JavaScript.

index.js
console.log(Number.MAX_SAFE_INTEGER); // 9007199254740991
📝 Note

The Number object is a wrapper object allowing you to work with numerical values. A Number object is created using the Number() constructor.

index.js
let x = new Number(123);
console.log(x); // [Number: 123]

Conclusion​

In this section, you learned how to create and manipulate numbers in JavaScript. You also learned about the different methods that can be used to manipulate numbers. In the next section, you will learn about strings in JavaScript.