Ability to extend the cli

Clear and concise description of the problem

I’m currently creating a SSR plugin for Vite, I would like to give the user the ability to start the server as SPA mode too.

But if I run something like vite --spa will give an error:

throw new CACError(`Unknown option \`${name.length > 1 ? `--${name}` : `-${name}`}\``);

Suggested solution

just add a cli option to the Plugin interface, pass the vite cli object to it, this pseudocode shows it adds an additional option to the serve command.

{
  name: 'foo',
  cli(cli: CAC) {
    const serveCommand = cli.commands.find(({name})=> name==='[root]')
    serveCommand.option('--spa', `start dev server in SPA mode`)
  }
}

I’ve been saw lots of plugin creators create a separated cli just for there plugin, it really should be a part of the vite command itself, this way, fits so natural and saving time, plus giving a change to add additional options to the default commands.

What you guys think about this?

[patak-dev]

If we allow extending the vite cli, we need to start thinking about possible collisions with future features. At this point, I agree that it is better to avoid the extra complexity in core. You could create an extensible-vite package to be used by others if they think that this approach has merits.

[yuanjinyong]

I find there is a “allowUnknownOptions” property in vite/dist/node/cli.js. And it used at

  checkUnknownOptions() {
    const {options, globalCommand} = this.cli;
    if (!this.config.allowUnknownOptions) {
      for (const name of Object.keys(options)) {
        if (name !== "--" && !this.hasOption(name) && !globalCommand.hasOption(name)) {
          throw new CACError(`Unknown option \`${name.length > 1 ? `--${name}` : `-${name}`}\``);
        }
      }
    }
  }

I tried change the code vite/dist/node/cli.js as following:

cli
    .command('build [root]').allowUnknownOptions()
    .option('--target <target>', `[string] transpile target (default: 'modules')`)

Add a allowUnknownOptions() call after command init method, then the vite build command will ignore unknown args.

But how can I set allowUnknownOptions to true do not change the source code? Because I want to pass some args to my vite plugin.