Web3.js: web3.utils.sha3 doesn't take a BN type argument.

[nujabes403]

There is a example which takes an BN type argument in https://web3js.readthedocs.io/en/1.0/web3-utils.html#sha3.

However, it throws an error when take an argument with BN type. like below:
TypeError: str.slice is not a function

I think example is wrong, we should fix it.

[joshstevens19]

You are correct - in theory it should only accept a string as Hash.keccak256 can only take a string, we have 2 options here

1 - Make web3.utils.sha3 toString anything which comes in which means it will then will be able to accept any number or BN or string which could be nice
2 - Update docs + types to only accept a string all the time

@nivida happy to do this in PR #2082 as it effects the types as well - let me know which option you fancy!

@nujabes403 Thanks for spotting this dude 👍

[nujabes403]

@joshstevens19 Thank you.

Accepting number as an argument could be confusing.
How about only transforming BN instance to string type through .toString(10)?

[joshstevens19]

Well they should be able to pass BN which the function can handle. BN has a toString() function on it already so its as simple as new Bn(3).toString().

I think parameter type should accept string | BN and in method if it's a object and not a string we do web3.utils.isBN(value) and if that's true then we turn it into a string so Hash.keccak256 can do it's magic 👍 think that would work nicely and means it's sticking to the public api docs. (as i'm guessing it was mean't to work that way 😄)

[nivida]

I've closed it because the fix is now merged.