Comment by 11235813213455

  things.every(thing => thing.type == 'hat' && thing.color == 'green')

now negating this gives:

  things.some(things => thing.type != 'hat' || thing.color != 'green')

So liar has something that is not a hat OR has something that is not green

So only "E) The liar has no green hats" is true