(Architecture) Grabbing Data for angular2 app. Directly check MongoDB or my Java REST?

I have a quick architecture question as this is one of my first web applications.

On the frontend I have an Angular2 NodeJS app, backend I have a Java server aggregating some data for me in a MongoDB.

My question is simple. Should I create REST controllers in my java server to get data from the database? Or call the database directly from the Angular app.

I am leaning towards the Java REST idea. I just feel it is more secure, easier to do, and when I scale I can have processing done in Java when a rest call is made.

But I am worried this may slow things down too much? I can directly call the database and get info to put on my angular site. Does anyone know if this is a real concern for speed?

Keep in mind the data returned from the calls could be thousands of lines of JSON and hundreds of objects.

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