Lifecycle-based Plugin Support

[ulivz]

Background

We have discussed a lot about the plugin: the long discussion & vote, and these awesome PRs: #196 and #216,

But when I start to develop plugin at many different situations, I find that the really appropriate plugin mechanism must delay the timing of execution. i.e. we need to support life cycle to let plugin developers to be able to do what they want to do at the right moment.

In order to better describe the PR, I drew these two pictures.

vuepress dev    

vuepress build    

As shown above, and as we discussed earlier, if we just execute all the plugins at the end of the prepare, then once a plugin has written some files to outDir, then you will never see it, which is too bad.

So for now, a plugin would be like this:

module.exports = async function vuepressPluginCustomDomain({ domain } /** only extra plugin options**/) {
  this

   // Execute when prepare is finished, if it's in `build`, the ourDir has been emptied.
   // You do mix extra data and options here before APP launched.
  .ready(() => {
    console.log('Used vuepress-plugin-custom-domain')
  })

  // Execute at the first end of webpack compilation.
  // You can generate extra files here.
  .compiled(async ({ outDir }) => {
    if (process.env.NODE_ENV !== 'production') {
      return
    }
    await fs.ensureDir(outDir)
    await fs.writeFile(path.resolve(outDir, 'CHAME'), domain, 'utf-8')
    console.log('Generated CHAME file.')
  })

   // Execute at each update, only for `dev` 
  .updated(() => {
    console.log('Updated')
  })
}

What are the benefits of doing so? for example, if we make the internal log at a default hook handler when we detect there is no other hook handlers, you can override it via plugins, so there would born a separate very handsome plugin.

Of course, It's still worth discussing how to make it better, feel free to give your thoughts.

Thanks~

[mdaffin]

Nice work.

One missing bit is to decide if we want to load the theme as a plugin (if say index.js exists in the theme root) or otherwise allow themes to add to the list of plugins to load. But this could be done as a future pull request.

[meteorlxy]

'CNAME' maybe