RFC: parseBase/toString for radixes outside 2/10/16 (maybe even 8)

[axic]

Does any other base than 2/10/16 (and maybe even 8) make any sense in day to day usage? Is there any use case for them today? The current implementation forces a single hardcoded alphabet consisting of 0-9,a-z,A-Z cut off at the radix.

Wouldn't it make more sense for those to support a user-supplied alphabet, similarly to the way base-x does it?

[indutny]

I think it should probably work for any bases from 1 to 36 as for regular JS numbers.

[indutny]

IMO, user supplied alphabet does not make sense, never heard about this sort of API in any serious big number library.

[axic]

I assume you are aware that the alphabet varies between big number libraries.

gmp (used by node-bigint):

For base in the range 2..36, digits and lower-case letters are used; for -2..-36, digits and upper-case letters are used; for 37..62, digits, upper-case letters, and lower-case letters (in that significance order) are used.

openssl (used by node-bignum aka bignum):
parser only supports base 2, 10 and 16, and toString only supports 10 and 16

bignumber.js:

For bases from 10 to 36, lower and/or upper case letters can be used to represent values from 10 to 35.
For bases above 36, a-z represents values from 10 to 35, A-Z from 36 to 61, and $ and _ represent 62 and 63 respectively (this can be changed by editing the ALPHABET variable near the top of the source file).

sjcl:
only supports base 2, 10, 16, 32, 64. Base 64 is the well known base64 alphabet. Base 32:

The encoding alphabet for sjcl.codec.base32 now matches that specified by the RFC 4648, rather than the extended hex alphabet.

bn.js:
compared to the above, given that bn.js is limited to <= base-36, the alphabet usage matches that of bignumber.js

[indutny]

Ok, I was a bit wrong then. Anyway, I don't feel like it is justified. Performance-wise it will mean a lot slower code. 3rd-party libraries could take toArray output and convert it to requested base if needed.

[indutny]

Sorry, closing the issue.