code: function loadPreset(descriptor, loader) {
    const config = Array.isArray(descriptor) ? descriptor : [descriptor];
    const [name, options = {}] = config;
    const { error: loaderError, module: getPreset } = loader(name);
  
    if (loaderError) {
      return {
        error: loaderError,
        name,
      };
    }
  
    if (typeof getPreset !== 'function') {
      return {
        error: new Error(
          `Expected the preset \`${name}\` to export a function, instead ` +
            `recieved: ${typeof getPreset}`
        ),
        name,
      };
    }
  
    let preset;
    try {
      preset = getPreset(options);
    } catch (error) {
      return {
        error,
        name,
        options,
      };
    }
  
    const { presets = [], plugins = [] } = preset;
  
    return {
      name,
      options,
      presets: presets.map(descriptor => loadPreset(descriptor, loader)),
      plugins: plugins.map(descriptor => loadPlugin(descriptor, loader)),
    };
  }
docs: Load the preset with the given loader
  @param {Descriptor} descriptor
  @param {Loader} loader