Some React Native apps need to directly manage your application users or at least be able to list a specific subset of them. Parse has powerful querying tools and they can also be used for your users in your social media app, for example. In this guide, you’ll learn how to use Parse.Query to perform realistic user querying in your React Native App using Parse JS SDK.

To build a user querying feature using Parse for a React Native App.

Any Parse query operation uses the Parse.Query object type, which will help you retrieve specific data from your database throughout your app. It is crucial to know that a Parse.Query will only resolve after calling a retrieve method (like Parse.Query.find or Parse.Query.get), so a query can be set up and several modifiers can be chained before actually being called.

To create a new Parse.Query, you need to pass as a parameter the desired Parse.Object subclass, which is the one that will contain your query results. An example for this guide use-case (Parse.User) can be seen below.

You can read more about the Parse.Query class here at the official documentation.

Let’s now take a look at some relevant queries that you may need to perform when managing or displaying users in your app. First of all, let’s perform a text search query, searching for users whose usernames contain the search value.

Note that that are at least two different ways to search for a string, each one having its specific applications and advantages. In most cases, you will want to use Parse.Query.matches to ensure case-insensitive results and avoid unexpected behavior in your code.

After performing this query, your user list on your app should be showing something like this:

In addition to string querying, you can also perform “exact” queries, when you want to retrieve objects that contain an exact value, just as with boolean fields. The next example will show how to retrieve users that are verified by email, through the emailVerified field.

Your app should now be updating your user list like this:

Another common example would be to apply orderings to your query. This can be done in two ways, either by using Parse.Query.ascending/Parse.Query.descending or Parse.Query.addAscending/Parse.Query.addDescending. The first case will override any other ordering and will be the only one that the query will take and the latter will concatenate with existing orderings, making multiple orderings possible.

Your app must now be ordering your queries like this:

Remember that all of the query constraints mentioned above can be chained and performed in a single query, improving your app usability for creating different filters and orderings that will work altogether. Here is the full code presenting all the query methods used in this guide:

At the end of this guide, you learned how to perform queries on Parse users on React Native. In the next guide, we will show you how to save and read data on Parse.