feat(compiler): Use a single compiler for multiple plugin instances

[jantimon]

This is a wip proposal to reuse a single compiler for multiple HtmlWebpackPlugin instances.

#962
#965

[vhmth]

@jantimon what's the best way I can incorporate this into my repo for testing? Would love to test build times and get back to you with any weird discrepancies.

[jantimon]

cd node_modules
git clone https://github.com/jantimon/html-webpack-plugin.git
git checkout feature/cache-file-timestamps

[vhmth]

@jantimon dopeness!

Went through and it seems like this might be the last thing to land on webpack-4? The webpack-4 branch I take it updates html-webpack-plugin@next automatically? If so, can pull from that and try this immediately.

[jantimon]

It's not published yet because of #972 but we might ship a new alpha soon 👍

[vhmth]

Ack ack!

[lock]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.