Feature: Add firestore.getAll() on the web

[fergusmeiklejohn]

Problem: fetching an array of docs by id

This is a solution using Promise.all() https://medium.com/@cambaughn/firestore-use-promise-all-instead-of-getall-on-the-web-301f4678bd05

This is how I wrote an action to do this:

    getData({ commit }, idArray) {
      const itemRefs = idArray.map(id => {
        return db
          .collection("myCollectionName")
          .doc(id)
          .get();
      });
      Promise.all(itemRefs)
        .then(docs => {
          let data = docs.map(doc => {
            return { ...doc.data(), id: doc.id };
          });
          commit("SET_DATA", data);
        })
        .catch(error => console.log(error));
    }

[louisameline]

Have you tried the fetchAndAdd action? It doesn't work as you'd expect?

[fergusmeiklejohn]

Have you tried the fetchAndAdd action? It doesn't work as you'd expect?

It's not clear in the docs that fetchAndAdd can do this. I have a collection of documents and I'm fetching a subset of them using an array of document IDs. I can't query to fetch them, I only know their IDs. The docs show dispatch('pokemon/fetchById', '001') but can we pass an array of IDs?

[louisameline]

I think it's something like dispatch('pokemon/fetchAndAdd', { clauses: { where: ['id', 'in', ['abc', 'def', 'ghi']] }})

Check the docs and https://firebase.google.com/docs/firestore/query-data/queries#query_operators

[fergusmeiklejohn]

This question on stack overflow discusses it: https://stackoverflow.com/questions/46721517/google-firestore-how-to-get-document-by-multiple-ids-in-one-round-trip We need to use firebase.firestore.FieldPath.documentId() It's limited to 10 items though. Promise.all() is unlimited in theory. I wonder if this would be useful for users:

const idArray = [...]
dispatch('pokemon/fetchById', idArray)

[louisameline]

What's wrong with the solution I gave you

[fergusmeiklejohn]

What's wrong with the solution I gave you

My understanding is that in limits a query to returning maximum 10 documents

[louisameline]

Ok, I didn't know that. For future reference it's limited to 10 parameters in the in clause, not 10 documents technically, but here yes the result is 10 docs.

Implementing a Promise.all is only a few lines but I feel it might be better to let the user handle it and just call by id as many times as required. Some docs might not get retrieved, so you might want to add more code than you've shown to handle this scenario.