Add simple querying

gatsby-node.js

@@ -1,24 +1,20 @@
-const report = require('gatsby-cli/lib/reporter');
-const firebase = require('firebase-admin');
-const crypto = require('crypto');
-
-const getDigest = id =>
-  crypto
-    .createHash('md5')
-    .update(id)
-    .digest('hex');
-
-exports.sourceNodes = async (
-  { actions },
-  { types, credential }
-) => {
-
-  try{
+const report = require("gatsby-cli/lib/reporter");
+const firebase = require("firebase-admin");
+const crypto = require("crypto");
+
+const getDigest = (id) => crypto.createHash("md5").update(id).digest("hex");
+
+exports.sourceNodes = async ({ actions }, { types, credential }) => {
+  try {
     if (firebase.apps || !firebase.apps.length) {
-      firebase.initializeApp({ credential: firebase.credential.cert(credential) });
+      firebase.initializeApp({
+        credential: firebase.credential.cert(credential),
+      });
     }
   } catch (e) {
-    report.warn('Could not initialize Firebase. Please check `credential` property in gatsby-config.js');
+    report.warn(
+      "Could not initialize Firebase. Please check `credential` property in gatsby-config.js"
+    );
     report.warn(e);
     return;
   }
@@ -28,8 +24,8 @@ exports.sourceNodes = async (
   const { createNode } = actions;
 
   const promises = types.map(
-    async ({ collection, type, map = node => node }) => {
-      const snapshot = await db.collection(collection).get();
+    async ({ collection, type, map = (node) => node, query }) => {
+      const snapshot = await queryDb(db, collection, query);
       for (let doc of snapshot.docs) {
         const contentDigest = getDigest(doc.id);
         createNode(
@@ -52,4 +48,15 @@ exports.sourceNodes = async (
   await Promise.all(promises);
 
   return;
-};
+};
+
+function queryDb(db, collection, query) {
+  let dbQuery = db.collection(collection);
+
+  if (query?.where) {
+    const { field, comparator, value } = query.where;
+    dbQuery = dbQuery.where(field, comparator, value);
+  }
+
+  return dbQuery.get();
+}