JavaScript - if 语句中 "Or"的简写

Question

if语句中是否有“或”条件的简写，我觉得重复是愚蠢的，在下面的情况下，“a”变量重复检查所有“或”条件:

  if(a != 'Cancelled' || a != 'Rejected' || a != 'Delivered' || a != 'Confirmed'){

    //execute something here

 }

Answer 1

if (['Cancelled', 'Rejected', 'Delivered', 'Confirmed'].indexOf(a) == -1) {
  // do stuff here
}