Handling empty collections and collections smaller than pageSize

mobidonia · Dec 20, 2016 · 01be73d · 01be73d
1 parent bdc7c76
commit 01be73d
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Showing 2 changed files with 76 additions and 15 deletions.
diff --git a/firebase-paginator.js b/firebase-paginator.js
@@ -1,5 +1,6 @@
 var isWindow = typeof window === 'object';
-var FirebasePaginator = function (ref, defaults) {
+
+function FirebasePaginator(ref, defaults) {
   var paginator = this;
   var defaults = defaults || {};
   var pageSize = defaults.pageSize ? parseInt(defaults.pageSize, 10) : 10;
@@ -112,10 +113,12 @@ var FirebasePaginator = function (ref, defaults) {
             } else {
               delete collection[keys[0]];
             }
+          } else if (isLastPage && keys.length < pageSize + 1) {
+            console.log('tiny page', keys.length, pageSize);
           } else if (isForward) {
             return setPage(); // force a reset if forward pagination overruns the last result
-          } else {
-            return setPage(undefined, true, true);
+          } else { 
+            return setPage(undefined, true, true); // Handle overruns
           }
 
           this.snap = snap;
@@ -189,17 +192,21 @@ var FirebasePaginator = function (ref, defaults) {
         var axios = require('axios');
         return axios.get(queryPath)
           .then(function (res) {
-            return Object.keys(res.data);
+            return Object.keys(res.data || {});
           });
       }
     };
 
     this.goToPage = function (pageNumber) {
       pageNumber = Math.min(this.pageCount, Math.max(1, parseInt(pageNumber)));
-      paginator.page = this.pages[pageNumber];
-      paginator.pageNumber = pageNumber;
-      paginator.isLastPage = pageNumber === Object.keys(paginator.pages).length;
-      paginator.ref = ref.orderByKey().limitToLast(pageSize).endAt(paginator.page.endKey);
+      if (Object.keys(this.pages).length) { // Null check for empty collections
+        paginator.page = this.pages[pageNumber];
+        paginator.pageNumber = pageNumber;
+        paginator.isLastPage = pageNumber === Object.keys(paginator.pages).length;
+        paginator.ref = ref.orderByKey().limitToLast(pageSize).endAt(paginator.page.endKey);
+      } else {
+        paginator.ref = ref.orderByKey().limitToLast(pageSize);
+      }
 
       return this.ref.once('value')
         .then(function (snap) {
@@ -212,7 +219,7 @@ var FirebasePaginator = function (ref, defaults) {
 
           paginator.snap = snap;
           paginator.keys = keys;
-          paginator.collection = collection;
+          paginator.collection = collection || {};
 
           fire('value', snap);
           if (paginator.isLastPage) {

diff --git a/test.js b/test.js
@@ -1,26 +1,31 @@
 var test = require('tape');
 var firebase = require('firebase');
 var path = 'firebasePaginator/collection';
+var smallCollectionPath = 'firebasePaginator/small-collection';
+var emptyCollectionPath = 'firebasePaginator/empty-collection';
 var firebaseConfig = require('./env.json').firebaseConfig;
 
 firebase.initializeApp(firebaseConfig);
 
 var FirebasePaginator = require('./firebase-paginator');
 var ref = firebase.database().ref(path);
-var populateCollection = function () {
+var smallCollectionRef = firebase.database().ref(smallCollectionPath);
+var emptyCollectionRef = firebase.database().ref(emptyCollectionPath);
+
+function populateCollection(count, ref) {
   return new Promise(function (resolve, reject) {
     var promises = [];
-    var i = 100;
+    var i = count;
 
     while (i--) {
-      promises.push(ref.push(100 - i));
+      promises.push(ref.push(count - i));
     }
 
     Promise.all(promises).then(resolve, reject);
   });
 };
 
-var testPage = function (paginator, length, start, end, testName) {
+function testPage(paginator, length, start, end, testName) {
   return new Promise(function (resolve, reject) {
     test(testName || `should return records ${start} to ${end}`, function (t) {
       paginator.once('value', function (snap) {
@@ -37,14 +42,63 @@ var testPage = function (paginator, length, start, end, testName) {
   });
 };
 
-ref.once('value')
+return ref.once('value')
   .then(function (snap) {
     if (snap.numChildren() === 100) {
       return true;
     } else {
-      return populateCollection();
+      return populateCollection(100, ref);
+    }
+  })
+  .then(function() {
+    return smallCollectionRef.once('value');    
+  })
+  .then(function(snap) {
+    if (snap.numChildren() == 3) {
+      return true;
+    } else {
+      return populateCollection(3, smallCollectionRef);
     }
   })
+  .then(function() {
+    return emptyCollectionRef.remove();
+  })
+  .then(function() { // Test empty collection inifite pagination
+    return new FirebasePaginator(emptyCollectionRef);
+  })
+  .then(function(paginator) {
+    return testPage(paginator, 0, undefined, undefined);
+  })
+  .then(function() { // Test empty collection finite pagination
+    return new FirebasePaginator(emptyCollectionRef, {
+      finite: true,
+      auth: firebaseConfig.secret
+    });
+  })
+  .then(function(paginator) {
+    return testPage(paginator, 0, undefined, undefined);
+  })
+  .then(function() { // Test small collection infinite pagination
+    return new FirebasePaginator(smallCollectionRef);
+  })
+  .then(function(paginator) {
+    return testPage(paginator, 3, 1, 3);
+  })
+  .then(function() {
+    return new FirebasePaginator(smallCollectionRef, {pageSize: 3});
+  })
+  .then(function(paginator) {
+    return testPage(paginator, 3, 1, 3);
+  })
+  .then(function() { // Test small collection finite pagination
+    return new FirebasePaginator(smallCollectionRef, {
+      finite: true,
+      auth: firebaseConfig.secret
+    });
+  })
+  .then(function(paginator) {
+    return testPage(paginator, 3, 1, 3);
+  })  
   .then(function () {
     var paginator = new FirebasePaginator(ref);