Number.prototype.toExponential()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The toExponential() method of Number values returns a string representing
this number in exponential notation.
Try it
Syntax
toExponential()
toExponential(fractionDigits)
Parameters
fractionDigitsOptional-
Optional. An integer specifying the number of digits after the decimal point. Defaults to as many digits as necessary to specify the number.
Return value
A string representing the given Number object in exponential notation
with one digit before the decimal point, rounded to
fractionDigits digits after the decimal point.
Exceptions
RangeError-
Thrown if
fractionDigitsis not between0and100(inclusive). TypeError-
Thrown if this method is invoked on an object that is not a
Number.
Description
If the fractionDigits argument is omitted, the number of digits
after the decimal point defaults to the number of digits necessary to represent the
value uniquely.
If you use the toExponential() method for a numeric literal and the
numeric literal has no exponent and no decimal point, leave whitespace(s) before the dot
that precedes the method call to prevent the dot from being interpreted as a decimal
point.
If a number has more digits than requested by the
fractionDigits parameter, the number is rounded to the nearest
number represented by fractionDigits digits. See the discussion
of rounding in the description of the toFixed() method, which also applies to toExponential().
Examples
Using toExponential
const numObj = 77.1234;
console.log(numObj.toExponential()); // 7.71234e+1
console.log(numObj.toExponential(4)); // 7.7123e+1
console.log(numObj.toExponential(2)); // 7.71e+1
console.log((77.1234).toExponential()); // 7.71234e+1
console.log((77).toExponential()); // 7.7e+1
Specifications
| Specification |
|---|
| ECMAScript Language Specification # sec-number.prototype.toexponential |
Browser compatibility
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