Mixing .splices and .* in observation does not work

[johannesr89]

https://jsfiddle.net/tqcrqran/70/

Please notice how the first div does not have the class called, but the other two do have it. Also please notice how sthElse is logged twice, but called is never logged.

[arthurevans]

Reproduced. Using foo.*,bar.* as the observer dependencies works; using foo.splices,bar.* as the argument does not, even though both foo.splices and bar.* are firing individually.

@azakus @kevinpschaaf

[kevinpschaaf]

This is as expected; see docs here: "Multi-property observers are not invoked until all dependent properties are defined (!== undefined)".

Since foo.splice is only defined as a result of a notification from an array mutation to foo via push/pop/splice/shift/unshift, such an observer wouldn't be called simply by setting the array. To catch every change to foo (both initial set and splice/mutations), listen for foo.* as @arthurevans suggested.

[johannesr89]

Then why is the observer observing just foo.splices called when setting foo?

[arthurevans]

@johannesr89 I wondered the same thing. I feel like there's a bug here somewhere, @kevinpschaaf, because the single-property observer on foo.splices is getting called, and by this logic, it shouldn't be.

[pomber]

Note that this issue is not related to bar wildcard. It also happens with (foo.splices, bar).
It's very confusing that the same path (foo.splices) works in a simple observer but doesn't work in a complex observer.