From ed9c8b591eaef11f856b7d641991851e093b7493 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Mon, 23 Oct 2017 11:20:55 +0000
Subject: [PATCH 01/13] Increase efficiency of Array updates made by
 FirestoreMixin.

Currently, when one document in a collection changes, an entirely new array is assigned to a property. It does not work well with dom-repeats, iron-lists etc. This change lays the groundwork for a more efficient solution.
---
 firebase-firestore-mixin.html | 90 +++++++++++++++++++++++++----------
 1 file changed, 64 insertions(+), 26 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 370a1e5..3e51ddf 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -6,10 +6,6 @@
 
 (context => {
   const MATCH_RE = /\{[a-z0-9_]+\}/gi;
-  const TRANSFORMS = {
-    doc: function(snap) { return iDoc(snap); },
-    collection: function(snap) { return snap.empty ? [] : snap.docs.map(doc => iDoc(doc)) }
-  }
 
   function parsePath(path) {
     let result;
@@ -27,14 +23,14 @@
     return whole;
   }
 
-	function collect(what, which) {
-		let res = {};
-		while (what) {
-			res = Object.assign({}, what[which], res); // Respect prototype priority
-			what = Object.getPrototypeOf(what);
-		}
-		return res;
-	};
+  function collect(what, which) {
+    let res = {};
+    while (what) {
+      res = Object.assign({}, what[which], res); // Respect prototype priority
+      what = Object.getPrototypeOf(what);
+    }
+    return res;
+  };
 
   function iDoc(snap) {
     if (snap.exists) {
@@ -153,18 +149,17 @@
 
         this._firestoreProps[name] = config;
 
-        // Create a method observer that will be called every time a templatized or observed property changes
-        let args = config.props.concat(config.observes).join(',');
-        if (args.length) { args = ',' + args; }
-        this._createMethodObserver(`_firestoreUpdateBinding('${type}','${name}'${args})`);
-
         if (!config.props.length && !config.observes.length) {
-          this._firestoreUpdateBinding(type,name);
+          this._firestoreUpdateBinding(name, type);
+        } else {
+          // Create a method observer that will be called every time a templatized or observed property changes
+          let args = config.props.concat(config.observes).join(',');
+          this._createMethodObserver(`_firestoreUpdateBinding('${name}', '${type}', ${args})`);
         }
       }
 
-      _firestoreUpdateBinding(type, name) {
-        this._firestoreUnlisten(name);
+      _firestoreUpdateBinding(name, type) {
+        this._firestoreUnlisten(name, type);
 
         const config = this._firestoreProps[name];
         const propArgs = Array.prototype.slice.call(arguments, 2, config.props.length + 2).filter(arg => arg);
@@ -178,10 +173,7 @@
         }
 
         const collPath = stitch(config.parts, propArgs);
-        const assigner = snap => {
-          this[name] = TRANSFORMS[type](snap);
-          this[name + 'Ready'] = true;
-        }
+        const assigner = this._firestoreAssigner(name, type);
 
         let ref = this.db[type](collPath);
         this[name + 'Ref'] = ref;
@@ -199,13 +191,59 @@
         }
       }
 
-      _firestoreUnlisten(name) {
+      _firestoreUnlisten(name, type) {
         if (this._firestoreListeners[name]) {
           this._firestoreListeners[name]();
           delete this._firestoreListeners[name];
         }
+        if (type === 'collection') {
+          this[name] = [];
+        }
+      }
+
+      _firestoreAssigner(name, type) {
+        if (type === 'doc') {
+          return (snap) => this._firestoreAssignDocument(name, snap);
+        } else if (type === 'collection') {
+          return (snap) => this._firestoreAssignCollection(name, snap);
+        } else {
+          throw new Error('Unknown listener type.')
+        }
+      }
+
+      _firestoreAssignDocument(name, snap) {
+        this[name] = iDoc(snap);
+        this[name + 'Ready'] = true;
+      }
+
+      _firestoreAssignCollection(name, snap) {
+        const allDocumentsChanged = snap.docs.length === snap.docChanges.length;
+        if (Array.isArray(this[name]) && !allDocumentsChanged) {
+          snap.docChanges.forEach((change) => {
+            switch (change.type) {
+              case 'added':
+                this.splice(name, change.newIndex, 0, iDoc(change.doc));
+                break;
+              case 'removed':
+                this.splice(name, change.oldIndex, 1);
+                break;
+              case 'modified':
+                if (change.oldIndex === change.newIndex) {
+                  this.splice(name, change.oldIndex, 1, iDoc(change.doc));
+                } else {
+                  this.splice(name, change.oldIndex, 1);
+                  this.splice(name, change.newIndex, 0, iDoc(change.doc));
+                }
+                break;
+              default:
+                throw new Error(`Unhandled document change: ${change.type}.`)
+            }
+          });
+        } else {
+          this[name] = snap.docs.map(iDoc);
+        }
       }
     }
   }
 })(window);
-</script>
\ No newline at end of file
+</script>

From d0a4870d98e9861c0e89192174d3c5c928e2c4c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 25 Oct 2017 16:57:03 +0000
Subject: [PATCH 02/13] Fix an issue with initail binding in FirestoreMixin.

This change fixes an issue which occurs when observed/bound properties are defined prior to a call of `connectedCallback`. Since _firestoreUpdateBinding method handles null and undefined values correctly, the `if` statement can be safely removed.
---
 firebase-firestore-mixin.html | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index b4e9a19..423aaac 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -162,9 +162,7 @@
         if (args.length) { args = ',' + args; }
         this._createMethodObserver(`_firestoreUpdateBinding('${type}','${name}'${args})`);
 
-        if (!config.props.length && !config.observes.length) {
-          this._firestoreUpdateBinding(type,name);
-        }
+        this._firestoreUpdateBinding(type,name);
       }
 
       _firestoreUpdateBinding(type, name) {

From e284cc42bd31e2a0adcb95c824708600a9cee702 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 25 Oct 2017 17:13:25 +0000
Subject: [PATCH 03/13] FirestoreMixin: throw an error on binding to properties
 with invalid type.

---
 firebase-firestore-mixin.html | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index b4e9a19..893d3a8 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -131,6 +131,15 @@
    */
   Polymer.FirestoreMixin = parent => {
     return class extends parent {
+      static _ensurePropertyTypeCorrectness(prop) {
+        if (prop.doc !== undefined && prop.type !== Object) {
+          throw new Error(`FirestoreMixin's \`doc\` can only be used with properties of type \`Object\`.`);
+        }
+        if (prop.collection !== undefined && prop.type !== Array) {
+          throw new Error(`FirestoreMixin's \`collection\` can only be used with properties of type \`Array\`.`);
+        }
+      }
+
       constructor() {
         super();
         this._firestoreProps = {};
@@ -140,6 +149,8 @@
 
       connectedCallback() {
         const props = collect(this.constructor, 'properties');
+        Object.values(props).forEach(this.constructor._ensurePropertyTypeCorrectness);
+
         for (let name in props) {
           if (props[name].doc) {
             this._firestoreBind('doc', props[name].doc, name, props[name].live, props[name].observes);

From 28210c0da8070e667695aa49cc6d267530c98bee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 25 Oct 2017 17:23:01 +0000
Subject: [PATCH 04/13] FirestoreMixin: ensure that it was not previously
 applied to the same class.

---
 firebase-firestore-mixin.html | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index b4e9a19..1cc0b3c 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -5,6 +5,7 @@
 }
 
 {
+  const TOKEN = Symbol('polymerfire-firestore-mixin');
   const PROPERTY_BINDING_REGEXP = /{([^{]+)}/g;
   const TRANSFORMS = {
     doc: function(snap) { return iDoc(snap); },
@@ -133,6 +134,12 @@
     return class extends parent {
       constructor() {
         super();
+
+        if (this[TOKEN]) {
+          throw new Error(`FirestoreMixin must not be applied more than once to the same class.`);
+        }
+
+        this[TOKEN] = true;
         this._firestoreProps = {};
         this._firestoreListeners = {};
         this.db = this.constructor.db || firebase.firestore();

From 3644a853916e566b5db5ca6ba2a0423bb2e664e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 25 Oct 2017 17:24:58 +0000
Subject: [PATCH 05/13] FirestoreMixin: add missing semicolons.

---
 firebase-firestore-mixin.html | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 645c8b4..4039c8f 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -211,7 +211,7 @@
         } else if (type === 'collection') {
           return (snap) => this._firestoreAssignCollection(name, snap);
         } else {
-          throw new Error('Unknown listener type.')
+          throw new Error('Unknown listener type.');
         }
       }
 
@@ -240,7 +240,7 @@
                 }
                 break;
               default:
-                throw new Error(`Unhandled document change: ${change.type}.`)
+                throw new Error(`Unhandled document change: ${change.type}.`);
             }
           });
         } else {

From 5982940df56c120ed380930f3b2836005215baf9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Thu, 26 Oct 2017 16:55:06 +0000
Subject: [PATCH 06/13] Add query property to _firestoreProps in
 FirestoreMixin.

---
 firebase-firestore-mixin.html | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index ac0258c..01ba8fe 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -141,38 +141,42 @@
       connectedCallback() {
         const props = collect(this.constructor, 'properties');
         for (let name in props) {
-          if (props[name].doc) {
-            this._firestoreBind('doc', props[name].doc, name, props[name].live, props[name].observes);
-          } else if (props[name].collection) {
-            this._firestoreBind('collection', props[name].collection, name, props[name].live, props[name].observes);
+          const options = props[name];
+          if (options.doc || options.collection) {
+            this._firestoreBind(name, options);
           }
         }
         super.connectedCallback();
       }
 
-      _firestoreBind(type, path, name, live = false, observes = []) {
-        const config = parsePath(path);
-        config.observes = observes;
-        config.live = live;
+      _firestoreBind(name, options) {
+        const defaults = {
+          live: false,
+          observes: [],
+        }
+        const parsedPath = parsePath(options.doc || options.collection);
+        const config = Object.assign({}, defaults, options, parsedPath);
+        config.type = config.doc ? 'doc' : 'collection';
 
         this._firestoreProps[name] = config;
 
         // Create a method observer that will be called every time a templatized or observed property changes
         let args = config.props.concat(config.observes).join(',');
         if (args.length) { args = ',' + args; }
-        this._createMethodObserver(`_firestoreUpdateBinding('${type}','${name}'${args})`);
+        this._createMethodObserver(`_firestoreUpdateBinding('${name}'${args})`);
 
         if (!config.props.length && !config.observes.length) {
-          this._firestoreUpdateBinding(type,name);
+          this._firestoreUpdateBinding(name);
         }
       }
 
-      _firestoreUpdateBinding(type, name) {
+      _firestoreUpdateBinding(name, ...args) {
         this._firestoreUnlisten(name);
 
         const config = this._firestoreProps[name];
-        const propArgs = Array.prototype.slice.call(arguments, 2, config.props.length + 2).filter(arg => arg);
-        const observesArgs = Array.prototype.slice.call(arguments, config.props.length + 2).filter(arg => arg);
+        const isDefined = (x) => x !== undefined;
+        const propArgs = args.slice(0, config.props.length).filter(isDefined);
+        const observesArgs = args.slice(config.props.length).filter(isDefined);
 
         if (propArgs.length < config.props.length || observesArgs.length < config.observes.length) {
           this[name] = null;
@@ -183,11 +187,11 @@
 
         const collPath = stitch(config.literals, propArgs);
         const assigner = snap => {
-          this[name] = TRANSFORMS[type](snap);
+          this[name] = TRANSFORMS[config.type](snap);
           this[name + 'Ready'] = true;
         }
 
-        let ref = this.db[type](collPath);
+        let ref = this.db[config.type](collPath);
         this[name + 'Ref'] = ref;
         this[name + 'Ready'] = false;
 

From 18ac794ad4b05b31ae6e5abd9616f00dc6514857 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 3 Jan 2018 15:25:49 +0000
Subject: [PATCH 07/13] Assign a null value to a document when it's listener is
 being deleted.

---
 firebase-firestore-mixin.html | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 4039c8f..a5476fd 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -200,9 +200,8 @@
           this._firestoreListeners[name]();
           delete this._firestoreListeners[name];
         }
-        if (type === 'collection') {
-          this[name] = [];
-        }
+
+        this[name] = type === 'collection' ? [] : null;
       }
 
       _firestoreAssigner(name, type) {

From ef9c2d022cc9e9c183477e4af2f6ee4915224cd1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 3 Jan 2018 15:29:18 +0000
Subject: [PATCH 08/13] Strict & more readable comparison in
 _firestoreAssignCollection method in FirestoreMixin.

---
 firebase-firestore-mixin.html | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index a5476fd..8036f33 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -220,8 +220,9 @@
       }
 
       _firestoreAssignCollection(name, snap) {
+        const propertyValueIsArray = Array.isArray(this[name])
         const allDocumentsChanged = snap.docs.length === snap.docChanges.length;
-        if (Array.isArray(this[name]) && !allDocumentsChanged) {
+        if (propertyValueIsArray && allDocumentsChanged === false) {
           snap.docChanges.forEach((change) => {
             switch (change.type) {
               case 'added':

From 35caf3a0ccb0fe8c23434d1583a876ea2245591e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 3 Jan 2018 15:54:44 +0000
Subject: [PATCH 09/13] Apply DRY rule and improve a name of
 _ensurePropertyTypeCorrectness in FirestoreMixin.

---
 firebase-firestore-mixin.html | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 893d3a8..08a7819 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -131,13 +131,18 @@
    */
   Polymer.FirestoreMixin = parent => {
     return class extends parent {
-      static _ensurePropertyTypeCorrectness(prop) {
-        if (prop.doc !== undefined && prop.type !== Object) {
-          throw new Error(`FirestoreMixin's \`doc\` can only be used with properties of type \`Object\`.`);
-        }
-        if (prop.collection !== undefined && prop.type !== Array) {
-          throw new Error(`FirestoreMixin's \`collection\` can only be used with properties of type \`Array\`.`);
+      static _assertPropertyTypeCorrectness(prop) {
+        const errorMessage = (listenerType, propertyType) =>
+          `FirestoreMixin's ${listenerType} can only be used with properties ` +
+          `of type ${propertyType}.`;
+        const assert = (listenerType, propertyType) => {
+          if (prop[listenerType] !== undefined && prop.type !== propertyType) {
+            throw new Error(errorMessage(listenerType, propertyType.name));
+          }
         }
+
+        assert('doc', Object);
+        assert('collection', Array);
       }
 
       constructor() {
@@ -149,7 +154,7 @@
 
       connectedCallback() {
         const props = collect(this.constructor, 'properties');
-        Object.values(props).forEach(this.constructor._ensurePropertyTypeCorrectness);
+        Object.values(props).forEach(this.constructor._assertPropertyTypeCorrectness);
 
         for (let name in props) {
           if (props[name].doc) {

From 5e5245edc3276e5500a091d66f0be280d65c0efd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 3 Jan 2018 16:07:15 +0000
Subject: [PATCH 10/13] Handle applying FirestoreMixin multiple times to the
 same element.

---
 firebase-firestore-mixin.html | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 1cc0b3c..97c8b89 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -5,7 +5,9 @@
 }
 
 {
-  const TOKEN = Symbol('polymerfire-firestore-mixin');
+  const CONSTRUCTOR_TOKEN = Symbol('polymerfire-firestore-mixin-constructor');
+  const CONNECTED_CALLBACK_TOKEN =
+    Symbol('polymerfire-firestore-mixin-connected-callback');
   const PROPERTY_BINDING_REGEXP = /{([^{]+)}/g;
   const TRANSFORMS = {
     doc: function(snap) { return iDoc(snap); },
@@ -135,17 +137,22 @@
       constructor() {
         super();
 
-        if (this[TOKEN]) {
-          throw new Error(`FirestoreMixin must not be applied more than once to the same class.`);
+        if (this[CONSTRUCTOR_TOKEN] === true) {
+          return;
         }
+        this[CONSTRUCTOR_TOKEN] = true;
 
-        this[TOKEN] = true;
         this._firestoreProps = {};
         this._firestoreListeners = {};
         this.db = this.constructor.db || firebase.firestore();
       }
 
       connectedCallback() {
+        if (this[CONNECTED_CALLBACK_TOKEN] === true) {
+          return;
+        }
+        this[CONNECTED_CALLBACK_TOKEN] = true;
+
         const props = collect(this.constructor, 'properties');
         for (let name in props) {
           if (props[name].doc) {

From fd12a0da1c1e3d270cd70ce0c49361eb28a2d09b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Wed, 3 Jan 2018 16:09:12 +0000
Subject: [PATCH 11/13] Simplify syntax in TRANSFORMS in FirestoreMixin.

---
 firebase-firestore-mixin.html | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 97c8b89..bc58a46 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -9,10 +9,6 @@
   const CONNECTED_CALLBACK_TOKEN =
     Symbol('polymerfire-firestore-mixin-connected-callback');
   const PROPERTY_BINDING_REGEXP = /{([^{]+)}/g;
-  const TRANSFORMS = {
-    doc: function(snap) { return iDoc(snap); },
-    collection: function(snap) { return snap.empty ? [] : snap.docs.map(doc => iDoc(doc)) }
-  }
 
   const isOdd = (x) => x & 1 === 1;
 
@@ -51,6 +47,11 @@
     }
   }
 
+  const TRANSFORMS = {
+    doc: iDoc,
+    collection: (snap) => snap.empty ? [] : snap.docs.map(iDoc),
+  }
+
   /**
    * This mixin provides bindings to documents and collections in a
    * Cloud Firestore database through special property declarations.

From 28f3e7da9324d7aecf79856ddc298fa33e0bb5e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Thu, 4 Jan 2018 17:14:05 +0000
Subject: [PATCH 12/13] Fix an issue with initial binding of properties in
 FirestoreMixin.

---
 firebase-firestore-mixin.html | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 1ef21a9..5d39589 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -169,7 +169,9 @@
         this[CONNECTED_CALLBACK_TOKEN] = true;
 
         const props = collect(this.constructor, 'properties');
-        Object.values(props).forEach(this.constructor._assertPropertyTypeCorrectness);
+        Object
+          .values(props)
+          .forEach(this.constructor._assertPropertyTypeCorrectness);
 
         for (let name in props) {
           const options = props[name];
@@ -192,16 +194,16 @@
 
         this._firestoreProps[name] = config;
 
-        if (config.props.length > 0 || config.observes.length > 0) {
+        const args = config.props.concat(config.observes);
+        if (args.length > 0) {
           // Create a method observer that will be called every time
           // a templatized or observed property changes
-          const args = config.props.concat(config.observes).join(',');
           const observer =
-            `_firestoreUpdateBinding('${name}', ${args})`
+            `_firestoreUpdateBinding('${name}', ${args.join(',')})`
           this._createMethodObserver(observer);
         }
 
-        this._firestoreUpdateBinding(name);
+        this._firestoreUpdateBinding(name, ...args.map(x => this[x]));
       }
 
       _firestoreUpdateBinding(name, ...args) {

From cbd73709b053e2d3db47337114efb0f6f20e19df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Natan=20S=C4=85gol?= <m@merlinnot.com>
Date: Mon, 8 Jan 2018 13:34:00 +0000
Subject: [PATCH 13/13] Fix 'propertyReady' in FirestoreMixin.

---
 firebase-firestore-mixin.html | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/firebase-firestore-mixin.html b/firebase-firestore-mixin.html
index 5d39589..3b58764 100644
--- a/firebase-firestore-mixin.html
+++ b/firebase-firestore-mixin.html
@@ -252,15 +252,17 @@
       }
 
       _firestoreAssigner(name, type) {
+        const makeAssigner = (assigner) => (snap) => {
+          assigner.call(this, name, snap);
+          this[name + 'Ready'] = true;
+        }
         if (type === 'doc') {
-          return (snap) => this._firestoreAssignDocument(name, snap);
+          return makeAssigner(this._firestoreAssignDocument);
         } else if (type === 'collection') {
-          return (snap) => this._firestoreAssignCollection(name, snap);
+          return makeAssigner(this._firestoreAssignCollection);
         } else {
           throw new Error('Unknown listener type.');
         }
-
-        this[name + 'Ready'] = true;        
       }
 
       _firestoreAssignDocument(name, snap) {