FieldValue.arrayRemove() to remove an object from array of objects based on property value

Question

I have a document with the following structure:

{
    "email" : "[email protected]",
    "value" : 100,
    "children" : [
                  {
                    "email" : "[email protected]",
                    "value" : 100
                  },
                  {
                    "email" : "[email protected]",
                    "value" : 200
                  }
                 ]
}

I want to remove all elements with the email [email protected] from the children array. I am able to remove one item if I pass the whole object to be removed like this:

FieldValue.arrayRemove(childObject)

But I want both the objects with the email [email protected] to be removed. Is there anyway to achieve this using FieldValue.arrayRemove()?

Doug Stevenson · Accepted Answer · 2020-01-11 17:17:40Z

8

The arrayRemove operation removes the exact item that you specify from the array. There is no way to pass a partial object and remove all array items that match the partial information. You will have to pass in each complete item that you want to remove.

If you don't know what those items are yet, you will typically have to first read the document, loop over the items in the array to remove them, and write the modified array back to the document.

edited Jan 11, 2020 at 17:17

Doug Stevenson

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answered Jan 11, 2020 at 14:58

Frank van Puffelen

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2 Comments

Nimish David Mathew Over a year ago

Is this feature likely to be supported in the future?

Frank van Puffelen Over a year ago

Nobody is actively working on adding partial array operations at the moment. If you'd like to cast your vote for them to be added, you can file a feature request. But for now, you will have to query-then-remove.

jbryanh · Accepted Answer · 2021-12-08 21:30:44Z

3

As an update, it is still the case that you must match the object exactly to remove it from an array. Additionally, of course, in the example above, he is querying for a value, which requires a query to see what matches.

However, depending on the logic: if you use a Map instead...for instance in the case above, adjusted:

"children" : 
    "[email protected]_100":
                      {
                        "email" : "[email protected]",
                        "value" : 100
                      },
    "[email protected]_200":
                      {
                        "email" : "[email protected]",
                        "value" : 200
                      }

You can simply use:

'[email protected]_200': FieldValue.delete(),

As of late, I've gravitated away from Lists to Maps for this reason.

answered Dec 8, 2021 at 21:30

jbryanh

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3 Comments

uerden Over a year ago

Hello, I want to change this '[email protected]_200' with 'children.${mail}', but not sure for the right syntax, can you help me with that?

jbryanh Over a year ago

String var = '[email protected]_200'; 'children.$var' should do it.

uerden Over a year ago

Unfortunately thats not working :/

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