javascript - Opposite of Number.toExponential in JS

Question

I need to get the value of an extremely large number in JavaScript in non-exponential form. Number.toFixed simply returns it in exponential form as a string, which is worse than what I had.

This is what Number.toFixed returns:

>>> x = 1e+31
1e+31
>>> x.toFixed()
"1e+31"

Number.toPrecision also does not work:

>>> x = 1e+31
1e+31
>>> x.toPrecision( 21 )
"9.99999999999999963590e+30"

What I would like is:

>>> x = 1e+31
1e+31
>>> x.toNotExponential()
"10000000000000000000000000000000"

I could write my own parser but I would rather use a native JS method if one exists.

Answer 1

You can use toPrecision with a parameter specifying how many digits you want to display:

x.toPrecision(31)

However, among the browsers I tested, the above code only works on Firefox. According to the ECMAScript specification, the valid range for toPrecision is 1 to 21, and both IE and Chrome throw a RangeError accordingly. This is due to the fact that the floating-point representation used in JavaScript is incapable of actually representing numbers to 31 digits of precision.