Correct way to push to an array in a model

Moss, Gregor gmoss at
Wed Apr 4 17:15:18 UTC 2018

Hi all,

I'm also interested in seeing what the "right" way to handle such a situation is. I recently encountered a case which was similar. I needed to create a fresh array and then add that to a model path, though I will almost certainly need to make modifications to that path in the future so some shorthand to accomplish that would be great.


-----Original Message-----
From: fluid-work <fluid-work-bounces at> On Behalf Of Steven Githens
Sent: April 3, 2018 17:08
To: Fluid Work <fluid-work at>
Subject: Correct way to push to an array in a model

Hi Fluid,

Just popping in to check on the correct way to push a value to an array using the change applier.
In the snippet below, I assume using fluid.copy is the correct way to do this, so I'm not editing the model in place outside of the change applier.

    var curUnsavedChanges = fluid.copy(that.model.unsavedChanges);
        description: description
    that.applier.change("unsavedChanges", curUnsavedChanges);

Do we think in the future we might have a few change applier types that could deal with something like this so it's not necessary to copy the item ( even in the future where models are immutable data structures ).

So you might go like:

that.applier.change("unsavedChanges", { description: description}, "ARRAY_PUSH");

And if unsavedChanges wasn't an array it would maybe fail, complain, or just assign it if the current val is a primitive.

fluid-work mailing list - fluid-work at To unsubscribe, change settings or access archives, see

More information about the fluid-work mailing list