# toStringAsExponential method

String toStringAsExponential ([int fractionDigits ])

Returns an exponential string-representation of `this`.

Converts `this` to a double before computing the string representation.

If `fractionDigits` is given then it must be an integer satisfying: `0 <= fractionDigits <= 20`. In this case the string contains exactly `fractionDigits` after the decimal point. Otherwise, without the parameter, the returned string uses the shortest number of digits that accurately represent this.

If `fractionDigits` equals 0 then the decimal point is omitted. Examples:

    1.toStringAsExponential();       // 1e+0
    1.toStringAsExponential(3);      // 1.000e+0
    123456.toStringAsExponential();  // 1.23456e+5
    123456.toStringAsExponential(3); // 1.235e+5
    123.toStringAsExponential(0);    // 1e+2

## Implementation

    String toStringAsExponential([int fractionDigits]);