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.
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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
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Exponentiation (** ) | 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
|
Legend
- Full support
- Full support
- No support
- No support
- User must explicitly enable this feature.
- User must explicitly enable this feature.