Exploring the wonders of LoopBack querying

Discovering loopback has been an enlightening experience for me. However, as I delve deeper into its functionalities, I've stumbled upon something unexpected.

I noticed that when executing queries, such as using the updateAll method, if a parameter is left undefined, the query will end up updating all data within the specified model.

Employee.updateAll(
    {
        username: undefined
    },
    {
        address: "ABC"
    }, function(err, results) { 
});

It leaves me wondering why the framework behaves this way and updates all data when a value is undefined.

javascriptloopbackjs

Answer №1

Full disclosure: I am a core developer involved in the development of the LoopBack framework.

In LoopBack, handling `undefined` is done in a way that treats it as if the property was never defined in the first place. This mirrors how JSON handles properties with `undefined` values by excluding them from the output string altogether.

Therefore, when you use a filter such as `{username: undefined}`, it is essentially interpreted as an empty filter `{}` which means "no conditions" and will match all records or model instances.

If your data is stored in an SQL database, using `null` instead of `undefined` should function correctly for you.

Dealing with empty (`undefined`) properties in other databases like NoSQL can be complex and there isn't a universal solution for this issue.

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