I did wonder about this, but then it’s actually somewhat in line with how it works for arrays:
[1,2,3] | 
#=> [1, 2, 3, 4]
For key-value-pairs I think it’s reasonable that elements with the same key would overwrite the existing value.
But you may have a good point, it’s not really that important, since for the rare cases one would want to do this
new is perfectly sufficient. I guess this was all based on some ideas re state management I wanted to try to try to borrow from Elm and then a concise syntax like this would be nice.