code: function customRenderFn(renderFn) {
    // The loader context.
    var _this = this
  
    return function (engine, template, locals, options) {
      return renderFn.call(_this, template, locals, options)
    }
  }
docs: Create a custom renderer from a custom render function.
  
  @this {webpack.loader.LoaderContext}
  @param {(s: string, l: any, o: any) => string} renderFn
  @returns {(e: any, t: string, l: any, o: any) => string}