# Exponentiation (**)

The exponentiation operator (`**`) returns the result of raising the first operand to the power of the second operand. It is equivalent to `Math.pow`, except it also accepts BigInts as operands.

## Syntax

```Operator: var1 ** var2
```

## Description

The exponentiation operator is right-associative: `a ** b ** c` is equal to `a ** (b ** c)`.

In most languages, such as PHP, Python, and others that have an exponentiation operator (`**`), the exponentiation operator is defined to have a higher precedence than unary operators, such as unary `+` and unary `-`, but there are a few exceptions. For example, in Bash, the `**` operator is defined to have a lower precedence than unary operators.

In JavaScript, it is impossible to write an ambiguous exponentiation expression. That is, you cannot put a unary operator (`+/-/~/!/delete/void/typeof`) immediately before the base number; doing so will cause a SyntaxError.

```-2 ** 2;
// 4 in Bash, -4 in other languages.
// This is invalid in JavaScript, as the operation is ambiguous.

-(2 ** 2);
// -4 in JavaScript and the author's intention is unambiguous.
```

Note that some programming languages use the caret symbol ^ for exponentiation, but JavaScript uses that symbol for the bitwise logical XOR operator.

## Examples

### Basic exponentiation

```2 ** 3   // 8
3 ** 2   // 9
3 ** 2.5 // 15.588457268119896
10 ** -1 // 0.1
NaN ** 2 // NaN
```

### Associativity

```2 ** 3 ** 2   // 512
2 ** (3 ** 2) // 512
(2 ** 3) ** 2 // 64```

### Usage with unary operators

To invert the sign of the result of an exponentiation expression:

```-(2 ** 2) // -4
```

To force the base of an exponentiation expression to be a negative number:

```(-2) ** 2 // 4
```

## Specifications

Specification
ECMAScript (ECMA-262)
The definition of 'Exponentiation operator' in that specification.

## Browser compatibility

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Desktop Mobile Server Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Chrome Full support 52 Edge Full support 14 Firefox Full support 52 IE No support No Opera Full support 39 Safari Full support 10.1 WebView Android Full support 51 Chrome Android Full support 52 Firefox Android Full support 52 Opera Android Full support 41 Safari iOS Full support 10.3 Samsung Internet Android Full support 6.0 nodejs Full support 7.0.0 Full support 7.0.0 Full support 6.5.0Disabled Disabled From version 6.5.0: this feature is behind the `--harmony` runtime flag.

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