Introduction
The toFixed() method in JavaScript is used to convert a number to a string, rounding the number to a specified number of decimal places. This method takes a single argument: the number of decimal places to round the number to.
In this article, we discuss how to use the toFixed() method in JavaScript.
Using the toFixed() method
To use the toFixed() method, you simply call it on a number, passing in the desired number of decimal places as the argument. The toFixed() method will then return a string representation of the number, rounded to the specified number of decimal places.
For example, suppose you have a number with the value 1.23456, and you want to convert it to a string with two decimal places. You could use the toFixed() method to do this, as shown in the following code:
let number = 1.23456;
let str = number.toFixed(2);
console.log(str);
Output
1.23
In this code, the toFixed() method is called on the number variable, passing in 2 as the argument. The toFixed() method then rounds the number variable to two decimal places, and returns a string representation of the rounded number. The resulting string is then assigned to the str variable, and is printed to the console.
In this example, the toFixed() method rounds the number 1.23456 to two decimal places, resulting in the string "1.23".
In addition to rounding numbers to a specified number of decimal places, the toFixed() method can also be used to convert numbers to strings with a specified number of significant digits. To do this, you simply pass in the desired number of significant digits as the argument to the toFixed() method.
For example, suppose you have a number with the value 123456789, and you want to convert it to a string with four significant digits. You could use the toFixed() method to do this, as shown in the following code:
let number = 123456789;
let str = number.toFixed(4);
console.log(str);
Output
123456789.0000
In this code, the toFixed() method is called on the number variable, passing in 4 as the argument. The toFixed() method then converts the number variable to a string with four significant digits, and returns the resulting string. The resulting string is then assigned to the str variable, and is printed to the console.
In this example, the toFixed() method converts the number 123456789 to a string with four significant digits, resulting in the string "123457000".
One thing to keep in mind when using the toFixed() method is that it only affects the string representation of a number, and does not change the actual value of the number. This means that if you want to perform further calculations on the rounded or significant digit number, you will need to convert the resulting string back to a number using the parseFloat() or parseInt() methods.
For example, suppose you have a number with the value 1.23456, and you want to round it to two decimal places and then add 1 to the result. You could use the toFixed() and parseFloat() methods to do this, as shown in the following code:
let number = 1.23456;
let str = number.toFixed(2);
let rounded = parseFloat(str);
console.log(rounded + 1);
Output
2.23
In this code, the toFixed() method is called on the number variable, passing in 2 as the argument. The toFixed() method then rounds the number variable to two decimal places, and returns a string representation of the rounded number. The resulting string is then assigned to the str variable.
Next, the parseFloat() method is called on the str variable, which converts the string representation of the rounded number back to a number. The resulting number is then assigned to the rounded variable.
Finally, the rounded variable is added to 1, and the result is printed to the console. In this example, the rounded variable has the value 2.23, so the result printed to the console is 2.23.
Summary
The toFixed() method in JavaScript is used to convert a number to a string, rounding the number to a specified number of decimal places or significant digits. This method takes a single argument: the number of decimal places or significant digits to round the number to. The toFixed() method only affects the string representation of a number, and does not change the actual value of the number. If you want to perform further calculations on the rounded or significant digit number, you will need to convert the resulting string back to a number using the parseFloat() or parseInt() methods.
References
Number.prototype.toFixed() - JavaScript | MDN (mozilla.org)
