code: function factory(pkg, location) {
    const isProd = process.env.NODE_ENV === "production";
    return [
      configure(pkg, location, "development", "module"),
      isProd && configure(pkg, location, "development", "umd"),
      isProd && configure(pkg, location, "production", "umd")
    ].filter(Boolean);
  }
docs: Return a Rollup configuration for a `pkg`.
  
  @return {Array}