@snowpack/plugin-typescript - Enhancement for references

[Kabe0]

I have been playing around with References in typescript which is quite a new concept and noticed that the plugin is executing a command on --watch that is not compatible with full project builds. This results in errors that .d.ts is not defined. To resolve this, we have to call the --build flag in the watch call in order to pass all the resources through the watch.

I prototyped a solution which was a bit hacky... Basically isEmit cannot be passed into the call if a --build is happening. Something like the following will work

function typescriptPlugin(snowpackConfig, {tsc, args, build} = {}) {
  return {
    name: '@snowpack/plugin-typescript',
    async run({isDev, log}) {
      const workerPromise = execa.command(
        `${tsc ? tsc : 'tsc'} ${args ? args : ''} ${build ? '--build' : '--noEmit'} ${isDev ? '--watch' : ''}`,
        {
          env: npmRunPath.env(),
          extendEnv: true,
          windowsHide: false,
          cwd: snowpackConfig.root || process.cwd(),
        },
      );

Alternative would be to make args actually replace --noEmit. So that the default value is --noEmit, but you can customise the whole chain... Something like so...

function typescriptPlugin(snowpackConfig, {tsc, args} = {}) {
  return {
    name: '@snowpack/plugin-typescript',
    async run({isDev, log}) {
      const workerPromise = execa.command(
        `${tsc ? tsc : 'tsc'} ${args ? args : '--noEmit'} ${isDev ? '--watch' : ''}`,
        {
          env: npmRunPath.env(),
          extendEnv: true,
          windowsHide: false,
          cwd: snowpackConfig.root || process.cwd(),
        },
      );

This option, while simpler, would cause problems for anyone using args expecting --noEmit to be set.