What is order by child in Firebase?

When using orderByChild() , data that contains the specified child key is ordered as follows: Children with a null value for the specified child key come first. Children with a value of false for the specified child key come next. If multiple children have a value of false , they are sorted lexicographically by key.

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What is the use of on () method in Firebase?

For reading a data from the Firebase Realtime database, Firebase has two methods on() and once() . on() method to retrieve data . This method is taking the event type as “value” and then retrieves the snapshot of the data. When we add val() method to the snapshot, we will get the JavaScript representation of the data.

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