The toString() method is a built-in method of the JavaScript Number object that allows you to convert any number type value into its string type representation.

How to Use the toString Method in JavaScript

To use the toString() method, you simply need to call the method on a number value. The following example shows how to convert the number value 24 into its string representation. Notice how the value of the str variable is enclosed in double quotation marks:

var num = 24;
var str = num.toString();

console.log(num); // 24
console.log(str); // "24"
Convert a number to string with toString() method

You can also call the toString() method immediately on a number value, but you need to add parentheses () to wrap the value or JavaScript will respond with an Invalid or unexpected token error.

The toString() method can also convert floating and negative numbers as shown below:

24.toString(); // Error: Invalid or unexpected token
(24).toString(); // "24"
(9.7).toString(); // "9.7"
(-20).toString(); // "-20"
Convert any type of numbers with toString() method

Finally, the toString() method also accepts the radix or base parameter. The radix allows you to convert a number from the decimal number system (base 10) to a string representing the number in other number systems.

Valid number systems for conversion include:

  • Binary system (base 2) that has 2 digits, 0 and 1
  • Ternary system (base 3) that has 3 digits 0, 1, and 2
  • Quaternary system (base 4) that has 4 digits, 0, 1, 2 and 3
  • And so on up to the Hexatridecimal system (base 36) that has the combination of Arabic numerals 0 to 9 and Latin letters A to Z
The syntax for toString() method, accepting radix parameter

The radix parameters accept a number type data with values ranging from 2 to 36. Here's an example of converting the decimal number 5 to its binary number (base 2) representation:

var str = (5).toString(2);

console.log(str); // "101"
Converting decimal number to binary number with toString() method

The decimal number 5 from the code above is converted to its binary number equivalent of 101 and then converted to a string.

How to Use Other Data Types with the toString() Method

Aside from converting the number type, the toString() method is also available for converting other data types into their string representations.

For example, you can convert an array type into its string representation as follows:

var arr = [ "Nathan", "Jack" ];
var str = arr.toString();

console.log(str); // "Nathan,Jack"
Convert an array to string with toString() method

Or a boolean type to string as shown below:

var bool = true;
var str = bool.toString();

console.log(str); // "true"

But I think you will most often use the toString() method to convert a number to a string instead of the others. That's what I usually do, too :)

Thanks for reading this tutorial

You may also be interested in other JavaScript tutorials that I've written, including Rounding Numbers with toFixed() Method and Calculating Absolute Value with Math.abs(). They are two of the most commonly asked JavaScript problems.

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