Create a DEFAULT_COMMON in Common

[jochem-brouwer]

In #1048 we discussed the possibility to export a DEFAULT_COMMON from Common. We use default commons across the packages, so for me it would make sense that we put this default on a centralized point (i.e. in Common).

[holgerd77]

My first-thought suggestion here would be to add an additional DEFAULT_CHAIN parameter (likely set to mainnet?) and then add a static constructor method Common.getDefaultCommon() using DEFAULT_CHAIN and DEFAULT_HARDFORK for instance creation.

[jochem-brouwer]

Yep, this makes sense!

[holgerd77]

I've made some search here for new Common({ chain: 'mainnet' }) and see where this applies and also looked into some code parts directly, and there are actually really few places where such a pattern is used in its plain form (so with no additional parameters for whatever reason).

Also this issue hasn't been addressed for some months so there seems to be not such an urgent need.

I will therefore cautiously close, feel free to reopen everyone who sees the need for this functionality (also no very strong opinion here, we can just add and that's it, think this would make some send and would eventually have some benefits).