[let和const](let%E5%92%8Cconst.md) [解构表达式变化](%E8%A7%A3%E6%9E%84%E8%A1%A8%E8%BE%BE%E5%BC%8F%E5%8F%98%E5%8C%96.md) [函数优化](%E5%87%BD%E6%95%B0%E4%BC%98%E5%8C%96.md) [map和reduce](map%E5%92%8Creduce.md) [nrm](nrm.md)