rollup-plugin.ts

var closure = require('google-closure-compiler-js')

function closureCompilerPlugin(options = {}){
  return {
    transformBundle(bundle){
      const compilation = Object.assign({}, options, {
        jsCode: options.jsCode ? options.jsCode.concat({ src: bundle }) : [{ src: bundle }]
      });

      const transformed = closure.compile(compilation);

      return { code: transformed.compiledCode, map: transformed.sourceMap };
    }
  }
}