feat(firestore option merging):

Author: posva

src/index.js

@@ -82,6 +82,9 @@ function bind ({ vm, key, ref }) {
 }
 
 function install (Vue, options) {
+  const strategies = Vue.config.optionMergeStrategies
+  strategies.firestore = strategies.methods
+
   Vue.mixin({
     created () {
       const { firestore } = this.$options

test/merging.spec.js

@@ -0,0 +1,38 @@
+import test from 'ava'
+import Vuefire from '../src'
+import {
+  db,
+  tick,
+  Vue
+} from './helpers'
+
+Vue.use(Vuefire)
+
+test.beforeEach(async t => {
+  t.context.mWithObjA = {
+    firestore: {
+      a: db.collection(1),
+      b: db.collection(2)
+    }
+  }
+
+  t.context.mWithObjB = {
+    firestore: {
+      a: db.collection(3),
+      c: db.collection(4)
+    }
+  }
+})
+
+test('should merge properties', t => {
+  const { mWithObjA, mWithObjB } = t.context
+  const vm = new Vue({
+    mixins: [mWithObjA, mWithObjB],
+    render: h => h('p', 'foo')
+  })
+  t.deepEqual(vm.$firestoreRefs, {
+    a: db.collection(3),
+    b: db.collection(2),
+    c: db.collection(4)
+  })
+})