Array helpers don't notify length change

[mbleigh]

If I use the built-in array mutation helpers, I would expect that they would properly notify not just on the array itself but also on its length. Right now I have an app with a counter and I have to manually notifyPath for the length each time I mutate the array.

[kevinpschaaf]

You can observe array.splices or array.*, which will get notified for any array mutations that affect the length of the array. Is that sufficient?

[mbleigh]

It works in terms of giving me a workaround without manual notification but
will then require me to memoize the length in a separate value instead of
being able to bind to it directly. Not the end of the world, but "counter
for an array property" is likely a common use case and I wouldn't be
surprised if other people run into the same issue.

On Wed, May 20, 2015 at 10:05 AM Kevin Schaaf [email protected]
wrote:

You can observe array.splices or array.*, which will get notified for any
array mutations that affect the length of the array. Is that sufficient?

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[kevinpschaaf]

I see, you'd like to bind the actual length length into the template, got it.

Sort-term, you could also do this, to avoid needed to make a property:

{{arrayLength(array.*)}}

arrayLength: function(change) {
   return change.base.length;
}

[mbleigh]

Nice!

On Fri, May 22, 2015, 8:27 PM Kevin Schaaf [email protected] wrote:

Closed #1573 #1573 via 0a06a72
0a06a72
.

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