How to query multiple values for a given key in firebase

Question

I attempted to use an 'OR' || statement in the equalTo() method, but this does not seem to work. Do I have to make a separate call for each value or is there a way to make conditional queries in firebase?

export const startSetContent = () => {
  return (dispatch, getState) => {
    const ref = database.ref("content");
    return ref
      .orderByChild("category")
      .equalTo('one-act-play' || 'ten-min-play' || 'full-length-play')
      .once('value')
      .then(snapshot => {
        const content = [];
        snapshot.forEach(childSnapshot => {
          content.push({
            id: childSnapshot.key,
            ...childSnapshot.val()
          });
        });
        dispatch(setContent(content));
      });
  };
}; 

Answer 1

What you typed there was a logical OR that JavaScript the programming language interprets. The result of the expression:

'one-act-play' || 'ten-min-play' || 'full-length-play'

is going to be simply:

'one-act-play'

So, Firebase Realtime Database will not see what you're trying to tell it.

Firebase Realtime Database has no concept of a kind of query that has ORs in it. You will have to query each type of thing separately and merge them together in your code as needed.

Answer 2

There is no concept of doing that you are asking for. You can do a turn around in which you can get the values on basis of one filter one-act-play using equalTo and rest you can filter on user end like:

export const startSetContent = () => {
  return (dispatch, getState) => {
    const ref = database.ref("content");
    return ref
      .orderByChild("category")
      .equalTo('one-act-play')
      .once('value')
      .then(snapshot => {
        const content = [];
        Object.keys(snapshot.val()).map(k => {
        if(k == 'ten-min-play' || k == 'full-length-play'){
        snapshot.forEach(childSnapshot => {
          content.push({
            id: childSnapshot.key,
            ...childSnapshot.val()
          });
        });
        }
        dispatch(setContent(content));
      });
  };
}; 

Or you can use library made to fulfil this kind of requirement Querybase