Formatting Numbers with the JavaScript toFixed()* Method [Examples]

This tutorial will show you how to format numbers to a fixed number of decimal places in the JavaScript programming language.

JavaScript Number Variables

JavaScript variables have different types. The type of a variable defines what kinds of values it can hold, and what can be done with that value.

Number typed variables hold numeric values and include a number of methods (built in functions) for performing numeric operations.

Number variables are declared by simply assigning a numeric value to a variable, or using the Number constructor.

var myNumber = 46;

or

var myNumber = Number(46);

Once a variable of the Number type has been declared with a numerical value, the toFixed() method is available to format it to a specified number of decimal places.

JavaScript Number.toFixed() Method Syntax

The toFixed() method will format a number to a fixed number of decimal places/digits. Here’s the Syntax:

number.toFixed(digits)

Note that:

• toFixed() does NOT modify the original number value/variable it is called from
• A STRING containing the formatted number is returned!
• digits is an optional parameter
  • If it is not provided, a default value of 0 will be used
• The number will be rounded if necessary
  • Zeros will be appended if necessary to reach the required number of decimal places

toFixed() Method Code Examples

let myNumber = 12345.6789

myNumber.toFixed()       // Returns '12346': Note rounding to nearest integer as default number of decimal places is 0
myNumber.toFixed(1)      // Returns '12345.7': Note number is rounded
myNumber.toFixed(6)      // Returns '12345.678900': Note zeros added to the end to reach number of desired decimal places
(1.23e+20).toFixed(2)  // Returns '123000000000000000000.00'
(1.23e-10).toFixed(2)  // Returns '0.00'
2.34.toFixed(1)        // Returns '2.3'
2.35.toFixed(1)        // Returns '2.4': Note number rounded up
2.55.toFixed(1)        // Returns '2.5': Note number rounded down
-2.34.toFixed(1)       // Returns -2.3 : Note that due to operator precedence, a string is not returned as the '-' operator has coerced the value back to a number
(-2.34).toFixed(1)     // Returns '-2.3': Note, above situation avoided as '-' operator is bracketed

Floating Point Numbers Warning

It’s also worth keeping in mind that floating point numbers are not always accurately represented by computers – check out our article on why this is and how to avoid running into the commonly associated problems.

View the original article from LinuxScrew here: Formatting Numbers with the JavaScript toFixed()* Method [Examples]