JavaScript Number toString() Method

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The JavaScript Number toString() method is used to change the variable type to string and returns a string representation. It accepts an optional parameter called 'radix', which is an integer that represents the base in the mathematical numeral system. The range of this parameter is between '2' and '36, and the default value of this parameter is '10'.

This method throws a 'RangeError' exception if the radix parameter value is not in the range of [2, 36].

Note: Both '0' and '-0' are represented as "0", while Infinity is represented as "Infinity" and NaN as "NaN".

Syntax

Following is the syntax of JavaScript Number toString() method −

toString(radix)

Parameters

This method accepts an optional parameter called 'radix', which is described below −

  • radix (optional) − Specifying the base to use for representing the number value.

Return value

This method returns a string representation of the specified number value.

Example 1

The example below will demonstrate how to use the JavaScript Number toString() method.

<html>
<head>
<title>JavaScript toString() Method</title>
</head>
<body>
<script>
   const val1  = 5494;
   const val2 = "1234";
   document.write("Given values = ", val1 , " and ", val2);
   document.write("<br>Result 1 = ", val1.toString());
   document.write("<br>Result 2 = ", val2.toString());
</script>
</body>
</html>

Output

Following is the output of the above program −

Given values = 5494 and 1234
Result 1 = 5494
Result 2 = 1234

Example 2

If the radix parameter is set to 20, this method returns a string representing of the specified number value using base 20.

<html>
<head>
<title>JavaScript toString() Method</title>
</head>
<body>
<script>
   const val  = 1234;
   const radix = 20;
   document.write("Given value = ", val);
   document.write("<br>Radix value = ", radix);
   document.write("<br>Result = ", val.toString(radix));
</script>
</body>
</html>

Output

After executing the above program, it will return a string representation of the number 1234 as −

Given value = 1234
Radix value = 20
Result = 31e

Example 3

Let's take a look at an example of the toString() method in real-time usage. In the following example, we used the toString() method inside the custom function called hexColor(). We use the Math.abs().toString() function to return a string representation of the given or passed value.

<html>
<head>
<title>JavaScript toString() Method</title>
</head>
<body>
<script>
   function hexColor(col){
      if(col < 256){
         return Math.abs(col).toString(16);
      }
      else{
         return 0;
      }
   }
   const val = 230;
   const val2 = "40";
   document.write("Given values = ", val, " and ", val2);
   document.write("<br>Result 1 = ", hexColor(val));
   document.write("<br>Result 2 = ", hexColor(val2));
</script>
</body>
</html>

Output

Once the above program is executed, it return a string representation for number 230 and 40 as − 

Given values = 230 and 40
Result 1 = e6
Result 2 = 28

Example 4

If the value of the optional parameter 'radix' is not within the range of [2, 100], the toString() method will throw a 'RangeError' exception.

<html>
<head>
<title>JavaScript toString() Method</title>
</head>
<body>
<script>
   const val = 1234;
   const radix = 1;
   document.write("Given value = ", val);
   document.write("<br>Radix value = ", radix);
   try {
      document.write("<br>Result = ", val.toString(radix));
   } catch (error) {
      document.write("<br>", error);  
   }
</script>
</body>
</html>

Output

The above program throws a 'RangeError' exception −

Given value = 1234
Radix value = 1
RangeError: toString() radix argument must be between 2 and 36
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