flow like the river

VISUALIZACION/node_modules/mongodb/lib/operations/count_documents.js

@@ -0,0 +1,37 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.CountDocumentsOperation = void 0;
+const aggregate_1 = require("./aggregate");
+/** @internal */
+class CountDocumentsOperation extends aggregate_1.AggregateOperation {
+    constructor(collection, query, options) {
+        const pipeline = [];
+        pipeline.push({ $match: query });
+        if (typeof options.skip === 'number') {
+            pipeline.push({ $skip: options.skip });
+        }
+        if (typeof options.limit === 'number') {
+            pipeline.push({ $limit: options.limit });
+        }
+        pipeline.push({ $group: { _id: 1, n: { $sum: 1 } } });
+        super(collection.s.namespace, pipeline, options);
+    }
+    executeCallback(server, session, callback) {
+        super.executeCallback(server, session, (err, result) => {
+            if (err || !result) {
+                callback(err);
+                return;
+            }
+            // NOTE: We're avoiding creating a cursor here to reduce the callstack.
+            const response = result;
+            if (response.cursor == null || response.cursor.firstBatch == null) {
+                callback(undefined, 0);
+                return;
+            }
+            const docs = response.cursor.firstBatch;
+            callback(undefined, docs.length ? docs[0].n : 0);
+        });
+    }
+}
+exports.CountDocumentsOperation = CountDocumentsOperation;
+//# sourceMappingURL=count_documents.js.map