Inspired by https://github.com/codediodeio/sveltefire & previous stuff I did here https://gist.github.com/metruzanca/e516aac42c79d16c894883e88d8af5f8

solidfire.ts

// Inspired by https://github.com/codediodeio/sveltefire & previous stuff I did here https://gist.github.com/metruzanca/e516aac42c79d16c894883e88d8af5f8

import { CollectionReference, DocumentData, Firestore, Query, QueryDocumentSnapshot, QuerySnapshot, collection, onSnapshot } from "firebase/firestore";
import { Accessor, from } from "solid-js";

type CollectionSignal<T> = {
  signal: Accessor<T[]>
  ref: CollectionReference<T> | Query<T> | null
}

export function createCollectionSignal<T>(
  firestore: Firestore,
  ref: string | Query<T, DocumentData> | CollectionReference<T, DocumentData>,
  startWith: T[] = []
): CollectionSignal<T> {
  let unsubscribe: () => void;

  // TODO firebase-admin
  // // Fallback for SSR
  // if (!globalThis.window) {
  //   const { subscribe } = writable(startWith);
  //   return {
  //     subscribe,
  //     ref: null,
  //   };
  // }

  // Fallback for missing SDK
  if (!firestore) {
    console.warn(
      "Firestore is not initialized. Are you missing FirebaseApp as a parent component?"
    );
    const signal = () => []
    return {
      signal,
      ref: null,
    }
  }

  const collectionRef = typeof ref === "string" ? collection(firestore, ref) : ref as CollectionReference;

  const signal = from<T[]>(set => {
    set(startWith)

    unsubscribe = onSnapshot(collectionRef, (snapshot: QuerySnapshot) => {
      const data = snapshot.docs.map((doc: QueryDocumentSnapshot) => {
        return { id: doc.id, ref: doc.ref, ...doc.data() } as T;
      });
      set(data);
    });

    return () => unsubscribe();
  })

  return {
    signal: signal as Accessor<T[]>,
    ref: collectionRef as CollectionReference<T>,
  };
}


// Example proxy to avoid having to import firestore everywhere
// export const proxyCreateCollectionSignal = <T>(
//   ref: string | Query<T, DocumentData> | CollectionReference<T, DocumentData>,
//   startWith: T[]
// ) => createCollectionSignal<T>(firestore, ref, startWith)