code: function getBuildingConfigs (target) {
    return target.map(({ dirname, name, version, entry, outDir, styleFilename }) => {
      return formats.map(format => {
        return {
          inputOptions: getInputOptions({ entry, outDir, styleFilename }),
          outputOptions: getOutputOptions({ outDir, name, version, format })
        }
      })
    }).reduce((prev, next) => prev.concat(next))
  }
docs: Get rollup building configurations
  @param target