⭐ feat(add): Added support for customCountFn. Set useCustomCount…

README.md

@@ -68,6 +68,7 @@ Returns promise
   - `[customLabels]` {Object} - Developers can provide custom labels for manipulating the response data.
   - `[pagination]` {Boolean} - If `pagination` is set to false, it will return all docs without adding limit condition. (Default: True)
   - `[useEstimatedCount]` - Enable [estimatedDocumentCount](https://docs.mongodb.com/manual/reference/method/db.collection.estimatedDocumentCount/) for larger datasets. Does not count based on given query, so the count will match entire collection size. (Default: False)
+  - `[useCustomCountFn]` - Enable custom function for count datasets. (Default: False)
   - `[forceCountFn]` {Boolean} - Set this to true, if you need to support \$geo queries. (Default: False)
   - `[read]` {Object} - Determines the MongoDB nodes from which to read. Below are the available options.
     - `[pref]`: One of the listed preference options or aliases.

src/index.js

@@ -14,6 +14,7 @@
  * @param {Number}              [options.page=1]
  * @param {Number}              [options.limit=10]
  * @param {Boolean}             [options.useEstimatedCount=true] - Enable estimatedDocumentCount for larger datasets. As the name says, the count may not abe accurate.
+ * @param {Function}            [options.useCustomCountFn=false] - use custom function for count datasets.
  * @param {Object}              [options.read={}] - Determines the MongoDB nodes from which to read.
  * @param {Function}            [callback]
  *
@@ -43,6 +44,7 @@ const defaultOptions = {
   options: {},
   pagination: true,
   useEstimatedCount: false,
+  useCustomCountFn: false,
   forceCountFn: false,
 };
 
@@ -65,6 +67,7 @@ function paginate(query, options, callback) {
     sort,
     pagination,
     useEstimatedCount,
+    useCustomCountFn,
     forceCountFn,
   } = options;
 
@@ -118,6 +121,8 @@ function paginate(query, options, callback) {
   } else {
     if (useEstimatedCount === true) {
       countPromise = this.estimatedDocumentCount().exec();
+    } else if (typeof useCustomCountFn === 'function') {
+      countPromise = useCustomCountFn();
     } else {
       countPromise = this.countDocuments(query).exec();
     }

tests/index.js

@@ -476,6 +476,42 @@ describe('mongoose-paginate', function () {
     });
   });
 
+  it('count Custom Fn works', function (done) {
+    Book.paginate(
+      {},
+      {
+        useCustomCountFn: function () {
+          return 100;
+        },
+      },
+      function (err, result) {
+        expect(err).to.be.null;
+        expect(result).to.be.an.instanceOf(Object);
+        assert.isNumber(result.totalDocs, 'totalDocs is a number');
+        expect(result.totalDocs).to.equal(100);
+        done();
+      }
+    );
+  });
+
+  it('count Custom Fn with Promise return works', function (done) {
+    Book.paginate(
+      {},
+      {
+        useCustomCountFn: function () {
+          return Promise.resolve(100);
+        },
+      },
+      function (err, result) {
+        expect(err).to.be.null;
+        expect(result).to.be.an.instanceOf(Object);
+        assert.isNumber(result.totalDocs, 'totalDocs is a number');
+        expect(result.totalDocs).to.equal(100);
+        done();
+      }
+    );
+  });
+
   after(function (done) {
     mongoose.connection.db.dropDatabase(done);
   });