From 41b4cc856ed5feed7eba8bffa1ae816dd88ba610 Mon Sep 17 00:00:00 2001
From: Mike Woofter <mike.woofter@mongodb.com>
Date: Wed, 30 Aug 2023 11:06:39 -0500
Subject: [PATCH 1/3] add comments

---
 source/code-snippets/crud/arrayFilters.js     | 35 +++++++++++++++++++
 source/code-snippets/indexes/text.js          |  6 ++++
 .../code-snippets/monitoring/cpm-subscribe.js |  2 ++
 .../code-snippets/usage-examples/distinct.js  |  9 +++--
 source/code-snippets/usage-examples/find.js   | 10 ++++--
 .../code-snippets/usage-examples/findOne.js   |  7 ++--
 .../usage-examples/insertMany.js              |  9 +++--
 .../usage-examples/replaceOne.js              | 10 ++++--
 .../crud/write-operations/embedded-arrays.txt |  2 +-
 9 files changed, 77 insertions(+), 13 deletions(-)

diff --git a/source/code-snippets/crud/arrayFilters.js b/source/code-snippets/crud/arrayFilters.js
index 818fa2028..58094afeb 100644
--- a/source/code-snippets/crud/arrayFilters.js
+++ b/source/code-snippets/crud/arrayFilters.js
@@ -7,9 +7,12 @@ const client = new MongoClient(uri);
 
 async function printData() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const myDB = client.db("test");
     const myColl = myDB.collection("testColl");
 
+    // Print all documents 
     console.log(JSON.stringify(await myColl.find().toArray()));
   } finally {
     await client.close();
@@ -18,18 +21,28 @@ async function printData() {
 
 async function runFirstArrayElement() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const myDB = client.db("test");
     const myColl = myDB.collection("testColl");
 
+    // Print the result
     console.log(JSON.stringify(await myColl.find().toArray()));
 
     // start firstArrayElement example
+    // Query for all elements in entries array where x is a string
     const query = { "entries.x": { $type : "string" } };
+
+    // For each matched element, increase value of y by 33
     const updateDocument = {
       $inc: { "entries.$.y": 33 }
     };
+
+    // Execute the update operation
     const result = await myColl.updateOne(query, updateDocument);
     // end firstArrayElement example
+
+    // Print the result
     console.log(result.modifiedCount);
     console.log(JSON.stringify(await myColl.find().toArray()));
   } finally {
@@ -39,19 +52,30 @@ async function runFirstArrayElement() {
 
 async function runAllArrayElements() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const myDB = client.db("test");
     const myColl = myDB.collection("testColl");
 
+    // Print all documents 
     console.log(JSON.stringify(await myColl.find().toArray()));
 
     // start allArrayElement example
+    // Query for all documents where date is May 15, 2023
     const query = { date: "5/15/2023" };
+
+    // For each matched document, remove duration field from calls array 
     const updateDocument = {
       $unset: { "calls.$[].duration": "" }
     };
+
+    // Execute the update operation
     const result = await myColl.updateOne(query, updateDocument);
     // end allArrayElement example
+    
     console.log(result.modifiedCount);
+    
+    // Print all documents 
     console.log(JSON.stringify(await myColl.find().toArray()));
   } finally {
     await client.close();
@@ -60,16 +84,24 @@ async function runAllArrayElements() {
 
 async function arrayFiltersIdentifier() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const myDB = client.db("test");
     const myColl = myDB.collection("testColl");
 
+    // Print all documents 
     console.log(JSON.stringify(await myColl.find().toArray()));
 
     // start arrayFiltersIdentifier example
+    // Query for all documents where date is November 12, 2023
     const query = { date: "11/12/2023" };
+    
+    // For each matched document, change the quantity of items to 2 
     const updateDocument = {
       $mul: { "items.$[i].quantity": 2 }
     };
+
+    // Update only non-oil items used for fried rice 
     const options = {
       arrayFilters: [
         {
@@ -78,10 +110,13 @@ async function arrayFiltersIdentifier() {
         }
       ]
     };
+
+    // Execute the update operation
     const result = await myColl.updateOne(query, updateDocument, options);
     // end arrayFiltersIdentifier example
     console.log(result.modifiedCount);
 
+    // Print all documents 
     console.log(JSON.stringify(await myColl.find().toArray()));
   } finally {
     await client.close();
diff --git a/source/code-snippets/indexes/text.js b/source/code-snippets/indexes/text.js
index 14c88d321..c2950e378 100644
--- a/source/code-snippets/indexes/text.js
+++ b/source/code-snippets/indexes/text.js
@@ -10,6 +10,7 @@ const client = new MongoClient(uri);
 async function run() {
   try {
     // begin-idx
+    // Get the database and collection on which to create the index 
     const myDB = client.db("testDB");
     const myColl = myDB.collection("blogPosts");
 
@@ -23,8 +24,13 @@ async function run() {
     console.log(`Index created: ${result}`);
 
     // begin-query
+    // Query for documents where body or title contain "life ahead"
     const query = { $text: { $search: "life ahead" } };
+    
+    // Show only the title field
     const projection = { _id: 0, title: 1 };
+
+    // Execute the find operation
     const cursor = myColl.find(query).project(projection);
     // end-query
     for await (const doc of cursor) {
diff --git a/source/code-snippets/monitoring/cpm-subscribe.js b/source/code-snippets/monitoring/cpm-subscribe.js
index 28571f524..34ae3f525 100644
--- a/source/code-snippets/monitoring/cpm-subscribe.js
+++ b/source/code-snippets/monitoring/cpm-subscribe.js
@@ -9,6 +9,8 @@ const client = new MongoClient(uri);
 
 // Replace <event name> with the name of the event you are subscribing to.
 const eventName = "<event name>";
+
+// Subscribe to the event
 client.on(eventName, (event) =>
   console.log("\nreceived event:\n", event)
 );
diff --git a/source/code-snippets/usage-examples/distinct.js b/source/code-snippets/usage-examples/distinct.js
index 5b1e2f0f6..ab25bee5b 100644
--- a/source/code-snippets/usage-examples/distinct.js
+++ b/source/code-snippets/usage-examples/distinct.js
@@ -7,18 +7,21 @@ const client = new MongoClient(uri);
 
 async function run() {
   try {
-    // define a database and collection on which to run the method
+    
+    // Get the database and collection on which to run the operation
     const database = client.db("sample_mflix");
     const movies = database.collection("movies");
 
-    // specify the document field
+    // Specify the document field to find distinct values for
     const fieldName = "year";
 
-    // specify an optional query document
+    // Specify an optional query document to limit results
     const query = { directors: "Barbra Streisand" };
 
+    // Execute the distinct operation
     const distinctValues = await movies.distinct(fieldName, query);
 
+    // Print the result
     console.log(distinctValues);
   } finally {
     await client.close();
diff --git a/source/code-snippets/usage-examples/find.js b/source/code-snippets/usage-examples/find.js
index 2137c5d53..0486e86d2 100644
--- a/source/code-snippets/usage-examples/find.js
+++ b/source/code-snippets/usage-examples/find.js
@@ -7,26 +7,30 @@ const client = new MongoClient(uri);
 
 async function run() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const database = client.db("sample_mflix");
     const movies = database.collection("movies");
 
-    // query for movies that have a runtime less than 15 minutes
+    // Query for movies that have a runtime less than 15 minutes
     const query = { runtime: { $lt: 15 } };
 
     const options = {
-      // sort returned documents in ascending order by title (A->Z)
+      // Sort returned documents in ascending order by title (A->Z)
       sort: { title: 1 },
       // Include only the `title` and `imdb` fields in each returned document
       projection: { _id: 0, title: 1, imdb: 1 },
     };
 
+    // Execute query 
     const cursor = movies.find(query, options);
 
-    // print a message if no documents were found
+    // Print a message if no documents were found
     if ((await movies.countDocuments(query)) === 0) {
       console.log("No documents found!");
     }
 
+    // Print returned documents
     for await (const doc of cursor) {
       console.dir(doc);
     }
diff --git a/source/code-snippets/usage-examples/findOne.js b/source/code-snippets/usage-examples/findOne.js
index e6aebdd2d..158b9d422 100644
--- a/source/code-snippets/usage-examples/findOne.js
+++ b/source/code-snippets/usage-examples/findOne.js
@@ -7,6 +7,8 @@ const client = new MongoClient(uri);
 
 async function run() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const database = client.db("sample_mflix");
     const movies = database.collection("movies");
 
@@ -14,15 +16,16 @@ async function run() {
     const query = { title: "The Room" };
 
     const options = {
-      // sort matched documents in descending order by rating
+      // Sort matched documents in descending order by rating
       sort: { "imdb.rating": -1 },
       // Include only the `title` and `imdb` fields in the returned document
       projection: { _id: 0, title: 1, imdb: 1 },
     };
 
+    // Execute query
     const movie = await movies.findOne(query, options);
 
-    // since this method returns the matched document, not a cursor, print it directly
+    // Since this method returns the matched document, not a cursor, print it directly
     console.log(movie);
   } finally {
     await client.close();
diff --git a/source/code-snippets/usage-examples/insertMany.js b/source/code-snippets/usage-examples/insertMany.js
index 3b462a7ef..93725a522 100644
--- a/source/code-snippets/usage-examples/insertMany.js
+++ b/source/code-snippets/usage-examples/insertMany.js
@@ -7,20 +7,25 @@ const client = new MongoClient(uri);
 
 async function run() {
   try {
+
+    // Get the database and collection on which to run the operation
     const database = client.db("insertDB");
     const foods = database.collection("foods");
 
-    // create an array of documents to insert
+    // Create an array of documents to insert
     const docs = [
       { name: "cake", healthy: false },
       { name: "lettuce", healthy: true },
       { name: "donut", healthy: false }
     ];
 
-    // this option prevents additional documents from being inserted if one fails
+    // Prevent additional documents from being inserted if one fails
     const options = { ordered: true };
 
+    // Execute insert operation
     const result = await foods.insertMany(docs, options);
+   
+    // Print result
     console.log(`${result.insertedCount} documents were inserted`);
   } finally {
     await client.close();
diff --git a/source/code-snippets/usage-examples/replaceOne.js b/source/code-snippets/usage-examples/replaceOne.js
index 854a1ba1b..7c9c9641b 100644
--- a/source/code-snippets/usage-examples/replaceOne.js
+++ b/source/code-snippets/usage-examples/replaceOne.js
@@ -7,17 +7,23 @@ const client = new MongoClient(uri);
 
 async function run() {
   try {
+    
+    // Get the database and collection on which to run the operation
     const database = client.db("sample_mflix");
     const movies = database.collection("movies");
 
-    // create a query for a movie to update
+    // Create a query to find the document to update
     const query = { title: { $regex: "The Cat from" } };
-    // create a new document that will be used to replace the existing document
+    
+    // Create the document that will replace the existing document
     const replacement = {
       title: `The Cat from Sector ${Math.floor(Math.random() * 1000) + 1}`,
     };
 
+    // Execute the replace operation
     const result = await movies.replaceOne(query, replacement);
+    
+    // Print the result 
     console.log(`Modified ${result.modifiedCount} document(s)`);
   } finally {
     await client.close();
diff --git a/source/fundamentals/crud/write-operations/embedded-arrays.txt b/source/fundamentals/crud/write-operations/embedded-arrays.txt
index e2d325dd4..9374d2690 100644
--- a/source/fundamentals/crud/write-operations/embedded-arrays.txt
+++ b/source/fundamentals/crud/write-operations/embedded-arrays.txt
@@ -283,7 +283,7 @@ code:
    :language: javascript
    :start-after: start arrayFiltersIdentifier example
    :end-before: end arrayFiltersIdentifier example
-   :emphasize-lines: 3, 6-11
+   :emphasize-lines: 6, 11-16 
    :dedent:
 
 The update multiplied the ``quantity`` value by ``2`` for

From ace91e929b8b249e6ea960330587b357b80a3b79 Mon Sep 17 00:00:00 2001
From: Mike Woofter <108414937+mongoKart@users.noreply.github.com>
Date: Tue, 5 Sep 2023 12:34:54 -0500
Subject: [PATCH 2/3] Apply suggestions from code review

Co-authored-by: Rea Rustagi <85902999+rustagir@users.noreply.github.com>
---
 source/code-snippets/crud/arrayFilters.js         | 10 +++++-----
 source/code-snippets/usage-examples/distinct.js   |  2 +-
 source/code-snippets/usage-examples/findOne.js    |  2 +-
 source/code-snippets/usage-examples/replaceOne.js |  2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/source/code-snippets/crud/arrayFilters.js b/source/code-snippets/crud/arrayFilters.js
index 58094afeb..8efedae06 100644
--- a/source/code-snippets/crud/arrayFilters.js
+++ b/source/code-snippets/crud/arrayFilters.js
@@ -30,7 +30,7 @@ async function runFirstArrayElement() {
     console.log(JSON.stringify(await myColl.find().toArray()));
 
     // start firstArrayElement example
-    // Query for all elements in entries array where x is a string
+    // Query for all elements in entries array where the value of x is a string
     const query = { "entries.x": { $type : "string" } };
 
     // For each matched element, increase value of y by 33
@@ -42,7 +42,7 @@ async function runFirstArrayElement() {
     const result = await myColl.updateOne(query, updateDocument);
     // end firstArrayElement example
 
-    // Print the result
+    // Print all documents
     console.log(result.modifiedCount);
     console.log(JSON.stringify(await myColl.find().toArray()));
   } finally {
@@ -61,10 +61,10 @@ async function runAllArrayElements() {
     console.log(JSON.stringify(await myColl.find().toArray()));
 
     // start allArrayElement example
-    // Query for all documents where date is May 15, 2023
+    // Query for all documents where date is the string "5/15/2023"
     const query = { date: "5/15/2023" };
 
-    // For each matched document, remove duration field from calls array 
+    // For each matched document, remove duration field from all entries in calls array 
     const updateDocument = {
       $unset: { "calls.$[].duration": "" }
     };
@@ -93,7 +93,7 @@ async function arrayFiltersIdentifier() {
     console.log(JSON.stringify(await myColl.find().toArray()));
 
     // start arrayFiltersIdentifier example
-    // Query for all documents where date is November 12, 2023
+    // Query for all documents where date is the string "11/12/2023"
     const query = { date: "11/12/2023" };
     
     // For each matched document, change the quantity of items to 2 
diff --git a/source/code-snippets/usage-examples/distinct.js b/source/code-snippets/usage-examples/distinct.js
index ab25bee5b..df481ceb9 100644
--- a/source/code-snippets/usage-examples/distinct.js
+++ b/source/code-snippets/usage-examples/distinct.js
@@ -15,7 +15,7 @@ async function run() {
     // Specify the document field to find distinct values for
     const fieldName = "year";
 
-    // Specify an optional query document to limit results
+    // Specify an optional query document to narrow results
     const query = { directors: "Barbra Streisand" };
 
     // Execute the distinct operation
diff --git a/source/code-snippets/usage-examples/findOne.js b/source/code-snippets/usage-examples/findOne.js
index 158b9d422..2eb49a611 100644
--- a/source/code-snippets/usage-examples/findOne.js
+++ b/source/code-snippets/usage-examples/findOne.js
@@ -25,7 +25,7 @@ async function run() {
     // Execute query
     const movie = await movies.findOne(query, options);
 
-    // Since this method returns the matched document, not a cursor, print it directly
+    // Print the document returned by findOne()
     console.log(movie);
   } finally {
     await client.close();
diff --git a/source/code-snippets/usage-examples/replaceOne.js b/source/code-snippets/usage-examples/replaceOne.js
index 7c9c9641b..340bc1845 100644
--- a/source/code-snippets/usage-examples/replaceOne.js
+++ b/source/code-snippets/usage-examples/replaceOne.js
@@ -12,7 +12,7 @@ async function run() {
     const database = client.db("sample_mflix");
     const movies = database.collection("movies");
 
-    // Create a query to find the document to update
+    // Create a query for documents where the title contains "The Cat from"
     const query = { title: { $regex: "The Cat from" } };
     
     // Create the document that will replace the existing document

From 57d6c283eab42fb152796629ecf1a523bb9585b0 Mon Sep 17 00:00:00 2001
From: Mike Woofter <mike.woofter@mongodb.com>
Date: Tue, 5 Sep 2023 12:36:12 -0500
Subject: [PATCH 3/3] rr feedback

---
 source/code-snippets/crud/arrayFilters.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/source/code-snippets/crud/arrayFilters.js b/source/code-snippets/crud/arrayFilters.js
index 8efedae06..5db976727 100644
--- a/source/code-snippets/crud/arrayFilters.js
+++ b/source/code-snippets/crud/arrayFilters.js
@@ -33,7 +33,7 @@ async function runFirstArrayElement() {
     // Query for all elements in entries array where the value of x is a string
     const query = { "entries.x": { $type : "string" } };
 
-    // For each matched element, increase value of y by 33
+    // On first matched element, increase value of y by 33
     const updateDocument = {
       $inc: { "entries.$.y": 33 }
     };