Friendly note on unexpected side-effects of 2.1.5->2.1.6 transition

[ukstv]

Using marvellous uint8arrays library extensively. The recent change depends on multiformats module instead of previous multibase. Apparently, multiformats uses conditional exports in its package.json, and vanilla Jest can not handle those.

So, if some people start complaining on their tests failing with cryptic errors, like Cannot read property 'base16' of undefined, please know, this is due to Jest unable to load multiformats properly.

A solution I have for the downstream users is to use custom resolver for Jest (jest-resolver-enhanced), like in the following fragment of package.json:

{
  "jest": {
    "resolver": "jest-resolver-enhanced"
  },
}

Any other resolver capable of handling conditional exports is just as fine, but every one I know of, are unusable right now due to old age. Checked them all, IMO.

[achingbrain]

Ah, that's annoying, sorry about that.

I've just opened mikeal/ipjs#14 which when building multiformats with the changes in that PR means it works with jest for me locally. I'll get a multiformats release out as soon as it's merged.

In the mean time please use your custom resolver or pin uint8arrays to 2.1.5.

[achingbrain]

This should be fixed in multiformats@9.4.2. I've published uint8arrays@2.1.7 which sets this as the minimum version of multiformats required.

Please let me know if this still causes you problems.

[achingbrain]

Closing this as it should be fixed, please re-open if you continue to see problems.

[ukstv]

Thanks @achingbrain

[alexeygorbachevsky]

@achingbrain It seems the issue is being reproduced for now. I had the error "Cannot read property 'base16' of undefined" and fixed it only via resolver as was suggested above ->
{
"jest": {
"resolver": "jest-resolver-enhanced"
},
}