where do we get the inner and outer variables?
You don't have to get those variables.
The inner and outer variables are used as placeholders. If you see in the arrayFilter we are modifying the ._id part of these variables.
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where do we get the inner and outer variables?
You don't have to get those variables.
The inner and outer variables are used as placeholders. If you see in the arrayFilter we are modifying the ._id part of these variables.