[SOLVED] Fetch Data from WatermelonDB in React

Fetch Data from WatermelonDB in React

I am using WatermelonDB as a local database of my app. I have a method getPlaces() inside a class AccessDB:

static async getPlaces() {
        const postsCollection = database.collections.get('places');
        const allPosts = await postsCollection.query().fetch();
        return allPosts;
}

Calling getPlaces() using AccessDB.getPlaces() with async and await works. How can I fetch the results matching the query?

Solution

The variable allPosts is an array with all places in your case. So to access the properties of the places, you would do in a different class:

import AccessDB from './AccessDB';

and then somewhere for example

(async () => {
    try {
        const places = await AccessDB.getPlaces();

        var buffer = '';
        for (place in places) {
            buffer += places[place].name + '\n'
        }
        console.log(buffer)
    } catch(e) {console.log(e)}
})()

You have to be carefully when debugging with console.log, as

1) console.log skips outputs if executed fast one after the other, e.g. if you console.log the places[place].name every time in the for-loop above and

2) if you console.log(places) you see the same as if you console.log(database) which is very confusing. You would expect to see [Object object],[Object object]..., which you see when you use alert(places).