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JavaScript - Exponentiation Operator

Exponentiation Operator

The exponentiation operator in JavaScript is represented as **. The exponentiation operator takes two operands and returns the power of the first operand raised to the second.

The exponentiation operator can also accept the variables of the BigInt data type as operands. Also, it follows the property of associativity, which means a**b**c and a**(b**c) expressions give the same result.

The exponentiation operator evaluates the expression from right to left.

Syntax

We should follow the syntax below to use the exponentiation operator.

let pow = x ** y;

Return value

It returns the result of raising the first operand (x) to the power of the second operand (y).

Examples

Let's understand the exponentiation operator in details with the help of some examples.

Example

The example below defines the p and q variables containing the 2 and 3 values. After that, we used the exponentiation operator to get the PQ. In the output, you can observe the value of the 'pow' variable, which is 23, equal to 8.

<html>
<body>
   <div id = "output"></div>
   <script>
      let p = 2;
      let q = 3;
      let pow = p ** q;
      document.getElementById("output").innerHTML = 
	  "The value of p ** q: " + pow;
   </script>
</body>
</html>

It will produce the following result − 

The value of p ** q: 8

Example: Associativity of Exponentiation Operator

This example demonstrates that the exponentiation operator follows the associativity property and evaluates the expression from right to left.

Both expressions print the 6561 in the output, equal to the 38, where 8 equals the 23.

<html>
   <body>
   <div id="output"></div>
   <script>
      let p = 3;
      let q = 2;
      let r = 3;
      let pow1 = p ** q ** r;
      let pow2 = p ** (q ** r);
    
      document.getElementById("output").innerHTML = 
      "pow1 = " + pow1 + "<br>" +
      "pow2 = " + pow2;
   </script>
   </body>
</html>

It will produce the following result − 

pow1 = 6561
pow2 = 6561

Example: Exponentiation operator with BigInt variables

The below example demonstrates that the exponentiation operator can also be used with the bigint numbers. It returns the bigint value in the output.

<html>
<body>
   <div id = "output"></div>
   <script>
   let p = 10000000000000000000000000000n;
   let q = 2n;
   let pow = p ** q;
      document.getElementById("output").innerHTML = "pow = " + pow;
   </script>
</body>
</html>

It will produce the following result − 

pow = 100000000000000000000000000000000000000000000000000000000

Example: Exponentiation operator with non-numeric values

When you use the non-numeric value as an operand of the exponentiation operator, it converts the value to numeric and returns the result. If the operand can't be converted to the numeric value, it returns NaN in the output.

Here, it converts the '[]' to 0 and gives the correct result. The numeric value for the string '2a' is NaN, so it prints the NaN in the output. If the array contains a single numeric element, it parses the element. Otherwise, it evaluates NaN if the array contains multiple elements.

<html>
<body>
   <div id = "output"></div>
   <script>
      const output = document.getElementById("output");
      let pow = 2 ** []; // Number([]) = 0
      output .innerHTML = "10 ** [] = " + pow + "<br>";
      pow = [] ** 2; // Number([]) = 0
      output.innerHTML += "[] ** 2 = " + pow + "<br>";
      pow = 2 ** [2]; // Number([2]) = 2    
      output.innerHTML += "10 ** [2] = " + pow + "<br>";
      pow = "2" ** 2; // Number("2") = 2
      output.innerHTML += "2 ** 2 = " + pow + "<br>";
      pow = "2a" ** 2; // Number("2a") = NaN
      output.innerHTML += "2a ** 2 = " + pow + "<br>";
      pow = [2, 3] ** 2; // Number([2, 3]) = NaN
      output.innerHTML += "[2, 3] ** 2 = " + pow + "<br>";    
  </script>
</body>
</html>

It will produce the following result − 

10 ** [] = 1
[] ** 2 = 0
10 ** [2] = 4
2 ** 2 = 4
2a ** 2 = NaN
[2, 3] ** 2 = NaN
The exponentiation operator is an alternative to the pow() method of the Math() object.
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