JavaScript Number Methods

JavaScript provides a variety of methods that can be used with numbers to perform operations, manipulate data, and format output. Here are some commonly used number methods in JavaScript:

1. toFixed()

The toFixed() method rounds a number to a specified number of decimal places and returns a string. The argument passed to toFixed() is the number of decimal places to round to:

let num = 3.14159;
console.log(num.toFixed(2)); // Outputs: "3.14"

2. toPrecision()

The toPrecision() method rounds a number to a specified number of significant digits and returns a string. The argument passed to toPrecision() is the number of significant digits to round to:

let num = 123.456;
console.log(num.toPrecision(4)); // Outputs: "123.5"

3. toString()

The toString() method converts a number to a string:

let num = 42;
console.log(num.toString()); // Outputs: "42"

The toString() method can also take an optional argument that specifies the base to use when converting the number to a string. The default base is 10, but other bases can be used, such as 2 for binary or 16 for hexadecimal:

let num = 42;
console.log(num.toString(2)); // Outputs: "101010"
console.log(num.toString(16)); // Outputs: "2a"

4. isNaN()

The isNaN() method determines whether a value is NaN (not a number):

console.log(isNaN("hello")); // Outputs: true
console.log(isNaN(42)); // Outputs: false

5. isFinite()

The isFinite() method determines whether a value is a finite number:

console.log(isFinite(42)); // Outputs: true
console.log(isFinite(Infinity)); // Outputs: false

6. parseInt()

The parseInt() method converts a string to an integer. It takes an optional second argument that specifies the base to use when converting the string:

let numStr = "42";
console.log(parseInt(numStr)); // Outputs: 42

let hexStr = "2a";
console.log(parseInt(hexStr, 16)); // Outputs: 42

7. parseFloat()

The parseFloat() method converts a string to a floating-point number:

let numStr = "3.14";
console.log(parseFloat(numStr)); // Outputs: 3.14

Understanding how to use number methods in JavaScript is essential for performing various operations, manipulating data, and formatting output. By using methods like toFixed(), toPrecision(), toString(), isNaN(), isFinite(), parseInt(), and parseFloat(), you can create more powerful and flexible applications that perform complex calculations and data manipulation.