json pipe does not update on object change

[rolandjitsu]

Maybe it is by design, but when I use the json pipe on an object inside a ng-for, whenever I change the object from a directive, these changes are not reflected.

I have a repo where I actually use this and you can see it here.

[vicb]

/cc @gdi2290

[vicb]

The problem might be that test is checked by ref and if the ref does not change, json is no re-evaluated as pipes are pure fonctions.
/cc @vsavkin

[rolandjitsu]

@vicb test is actually an array of objects (I said object in the first post - my bad). Detection works when I change the length of the array, but it does not work when I change any of the object values inside the array.

In Angular 1.x there is a $watchCollection, for instancem which solves that issue when you need to watch for changes inside the array, because a simple $watch did not work (unless you specify the deep comparison option $watch(something, callback, true)).

I'm not quite sure how things work in Angular 2 though.

[vsavkin]

You should be able to do the following: {{ col | iterableDiff | json }}. iterableDiff transforms a reference check into a collection check.

[vsavkin]

We could also change json not to cache the value.

[rolandjitsu]

@vsavkin maybe json should not cache the values, but that would have an impact on performance I suppose.

[rolandjitsu]

@vsavkin using iterableDiff throws: Cannot find 'iterableDiff' pipe supporting object '[object Object]' in [{{ test | iterableDiff | json }} in null].

[PatrickJS]

darn :/ cache was a perf feature. Yeah I can update it. If we want to cache the ref we should just add a CachePipe or LRUPipe

{{ test | cache | json }}
{{ test | lru('namespace') | json }}

[PatrickJS]

I'm also running into this problem so I can't test locally. Although, the changes is just removing code and adding more tests
#2281

[rolandjitsu]

@gdi2290 I think that a cache pipe would be nice for those who do not want any changes reflected after the collection has been set.