Upgrade to Pattern Lab 3

[james-nash]

Purpose

Pattern Lab is working towards a major new v3 release which introduces quite a few changes compared to the 2.x ones. Version 3 will introduce some useful new features so we should aim to upgrade as soon as possible - potentially even experimenting with alpha releases now. This issue is to cover that work.

Note: We've already done some experimentation with upgrading to an early PL3 alpha release (that was available in early December 2017) in the pl3-upgrade branch, so that's probably a good place to start. However, it's possible that much has changed on more recent PL3 alphas so whoever picks up this task may want to consider starting afresh if that's easier. In that case, please delete the old pl3-upgrade branch.

Notable PL3 changes

• PL3 now has a CLI, so that the old "editions" are not necessarily required anymore (although, it should still be possible to invoke it via Gulp or similar)
• PL3 ships with a built-in dev server so pairing it with something like BrowserSync (as we do) is potentially redundant
  • Note, that the built-in server probably won't be as feature-rich as BrowserSync, so we may still want to use that over PL's built-in one
• PL3 aims to make it easier to customise or replace the UI skin it wraps around your patterns (the black bars with the menus).
  • Additionally, they are adding support for multiple front-ends
  • This could be useful for Improve global look and feel of the pattern library #106, Migrate Buildit brand guidelines into Pattern Lab #118 & Document Gravity goals and principles in Pattern Lab #119 since it would allow us to develop a "storefront" styleguide website that is built from our existing patterns (potentially in addition to the current "workshop" UI we have today)

Further reading

• Pattern Lab 3 goals
• Pattern Lab's 2.x - 3.x upgrade instructions
  • Note that Gravity uses a heavily customised equivalent to PL's standard edition-node-gulp