Simple Rollup plugin starter

my-plugins.js

// import { createFilter } from 'rollup-pluginutils'

function assign(target, source) {
  Object.keys(source).forEach((key) => {
    target[key] = source[key];
  });
  return target;
}

// const DEFAULT_HEADER = 'import React from \'react\';'

module.exports = (opts) => {
  opts = assign({}, opts || {});
  //   if (!opts.include) {
  //     throw Error('include option should be specified');
  //   }
  //   let filter = createFilter(opts.include, opts.exclude)
  //   let header = opts.header !== undefined ? opts.header : DEFAULT_HEADER

  return {
    name: 'add-import',

    transform(code, id) {
      console.log('MY PLUGIN', code);
      //   if (!filter(id)) return
      //   return {
      //     code: header + '\n' + code,
      //     map: { mappings: '' }
      //   }
    }
  };
};