DOCSP-29345 - Replace forEach (#671)

* replace forEach

* js feedback

Author: mongoKart

source/code-snippets/crud/cursor.js

@@ -6,14 +6,6 @@ const uri =
   "mongodb+srv://<user>:<password>@<cluster-url>?writeConcern=majority";
 const client = new MongoClient(uri);
 
-async function forEachIteration(myColl) {
-  // start foreach cursor example
-  const cursor = myColl.find({});
-  await cursor.forEach(doc => console.log(doc));
-  // end foreach cursor example
-  console.log(await myColl.countDocuments());
-}
-
 async function asyncIteration(myColl) {
   // start async cursor example
   const cursor = myColl.find({});
@@ -81,7 +73,6 @@ async function run() {
     const database = client.db("test");
     const orders = database.collection("orders");
 
-    await forEachIteration(orders);
     await asyncIteration(orders);
     await manualIteration(orders);
     await streamAPI(orders);

source/code-snippets/crud/startrek.js

@@ -23,7 +23,9 @@ async function word(movies) {
   if ((await movies.countDocuments(query)) === 0) {
     console.log("No documents found!");
   }
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  } 
 }
 
 async function phrase(movies) {
@@ -44,7 +46,9 @@ async function phrase(movies) {
   if ((await movies.countDocuments(query)) === 0) {
     console.log("No documents found!");
   }
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  } 
 }
 
 async function negation(movies) {
@@ -65,7 +69,9 @@ async function negation(movies) {
   if ((await movies.countDocuments(query)) === 0) {
     console.log("No documents found!");
   }
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  } 
 }
 
 async function relevance(movies) {
@@ -92,7 +98,9 @@ async function relevance(movies) {
   if ((await movies.countDocuments(query)) === 0) {
     console.log("No documents found!");
   }
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  } 
 }
 
 async function run() {

source/code-snippets/crud/theaters.js

@@ -24,7 +24,9 @@ async function proximity(theaters) {
   if ((await theaters.countDocuments(query)) === 0) {
     console.log("No documents found!");
   }
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  } 
 }
 
 async function range(theaters) {
@@ -55,7 +57,9 @@ async function range(theaters) {
   if ((await theaters.countDocuments(query)) === 0) {
     console.log("No documents found!");
   }
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  } 
 }
 
 async function run() {

source/code-snippets/quick-reference.js

@@ -16,7 +16,9 @@ async function query(coll) {
 async function queryMany(coll) {
   console.log("find");
   const cursor = coll.find({ year: 2005 });
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  }
 }
 
 async function insertOne(coll) {
@@ -108,7 +110,9 @@ async function watchStart(coll) {
 
 async function accessCursorIterative(coll) {
   const cursor = coll.find().limit(10);
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  }
 }
 
 async function accessCursorArray(coll) {
@@ -134,17 +138,23 @@ async function skipExample(coll) {
 
 async function sortExample(coll) {
   const cursor = coll.find().limit(50).sort({ year: 1});
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  }
 }
 
 async function projectExample(coll) {
   const cursor = coll.find().project({ _id: 0, year: 1, imdb: 1 });
-  await cursor.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  }
 }
 
 async function searchText(coll) {
   const result = coll.find({$text: { $search: 'zissou' }}).limit(30).project({title: 1});
-  await result.forEach(console.dir);
+  for await (const doc of cursor) {
+    console.dir(doc);
+  }
 }
 
 async function distinct(coll) {

source/code-snippets/usage-examples/find.js

@@ -27,8 +27,10 @@ async function run() {
       console.log("No documents found!");
     }
 
-    // replace console.dir with your callback to access individual elements
-    await cursor.forEach(console.dir);
+    for await (const doc of cursor) {
+      console.dir(doc);
+    }
+
   } finally {
     await client.close();
   }

source/code-snippets/usage-examples/find.ts

@@ -37,7 +37,9 @@ async function run() {
       console.warn("No documents found!");
     }
 
-    await cursor.forEach(console.dir);
+    for await (const doc of cursor) {
+      console.dir(doc);
+    } 
   } finally {
     await client.close();
   }

source/fundamentals/crud/query-document.txt

@@ -66,7 +66,9 @@ documents containing a field called "name" that has a value of "apples":
 
    const query = { "name": "apples" };
    const cursor = myColl.find(query);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 This code snippet returns the following results:
 
@@ -107,7 +109,9 @@ value greater than 5 and prints them out:
    // $gt means "greater than"
    const query = { qty: { $gt : 5 } };
    const cursor = myColl.find(query);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 This code snippet returns the following results:
 
@@ -131,7 +135,9 @@ that is not greater than 5 and prints them out:
 
    const query = { qty: { $not: { $gt: 5 }}};
    const cursor = myColl.find(query);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 This code snippet returns the following results:
 
@@ -179,7 +185,9 @@ field:
 
    const query = { microsieverts: { $exists: true } };
    const cursor = myColl.find(query);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 This code snippet returns the following results:
 
@@ -206,7 +214,9 @@ a remainder of 0:
    // $mod means "modulo" and returns the remainder after division
    const query = { qty: { $mod: [ 3, 0 ] } };
    const cursor = myColl.find(query);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 This code snippet returns the following results:
 

source/fundamentals/crud/read-operations/cursor.txt

@@ -51,7 +51,7 @@ pulling all matching documents into a collection in process memory.
 .. warning::
 
    Do not combine different cursor paradigms on a single cursor.
-   Operations such as ``hasNext()``, ``forEach()``, and ``toArray()``
+   Operations such as ``hasNext()`` and ``toArray()``
    each predictably modify the original cursor. If you mix these calls
    on a single cursor, you may receive unexpected results.
 
@@ -68,44 +68,14 @@ pulling all matching documents into a collection in process memory.
    fetch, the cursor is exhausted which means it ceases to respond to methods
    that access the results.
 
-.. _node-fundamentals-cursor-foreach:
-
-For Each Functional Iteration
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-You can pass a function to the `forEach() <{+api+}/classes/FindCursor.html#forEach>`__ method of any cursor to iterate through
-results in a functional style:
-
-.. literalinclude:: /code-snippets/crud/cursor.js
-   :language: javascript
-   :start-after: start foreach cursor example
-   :end-before: end foreach cursor example
-
-.. _node-fundamentals-cursor-array:
-
-Return an Array of All Documents
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-For use cases that require all documents matched by a query to be held
-in memory at the same time, use `toArray() <{+api+}/classes/FindCursor.html#toArray>`__.
-Note that large numbers of matched documents can cause performance issues
-or failures if the operation exceeds memory constraints. Consider using
-`forEach() <{+api+}/classes/FindCursor.html#forEach>`__ to iterate
-through results unless you want to return all documents at once.
-
-.. literalinclude:: /code-snippets/crud/cursor.js
-   :language: javascript
-   :start-after: start fetchAll cursor example
-   :end-before: end fetchAll cursor example
-
 .. _node-fundamentals-async-iteration:
 
 Asynchronous Iteration
 ~~~~~~~~~~~~~~~~~~~~~~
 
 Cursors implement the :mdn:`AsyncIterator
 <Web/JavaScript/Reference/Statements/for-await...of>` interface, which
-allows you to use cursors in ``for``...``await`` loops:
+allows you to use cursors in ``for await...of`` loops:
 
 .. literalinclude:: /code-snippets/crud/cursor.js
    :language: javascript
@@ -125,6 +95,23 @@ method to retrieve the subsequent element of the cursor:
    :start-after: start manual cursor example
    :end-before: end manual cursor example
 
+.. _node-fundamentals-cursor-array:
+
+Return an Array of All Documents
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For use cases that require all documents matched by a query to be held
+in memory at the same time, use the `toArray() <{+api+}/classes/FindCursor.html#toArray>`__
+method. Note that large numbers of matched documents can cause performance issues
+or failures if the operation exceeds memory constraints. Consider using
+the ``for await...of`` syntax to iterate
+through results rather than returning all documents at once.
+
+.. literalinclude:: /code-snippets/crud/cursor.js
+   :language: javascript
+   :start-after: start fetchAll cursor example
+   :end-before: end fetchAll cursor example
+
 Stream API
 ~~~~~~~~~~
 

source/fundamentals/crud/read-operations/distinct.txt

@@ -67,7 +67,9 @@ unique values of the ``borough`` field:
 
    // specify "borough" as the field to return values for
    const cursor = myColl.distinct("borough");
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 This code outputs the following ``borough`` values:
 
@@ -98,7 +100,9 @@ excludes restaurants in "``Brooklyn``":
 
    // find the filtered distinct values of "cuisine"
    const cursor = myColl.distinct("cuisine", query);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 In this case, the query filter matches every borough value except for "``Brooklyn``". This
 prevents ``distinct()`` from outputting one ``cuisine`` value, "``Middle Eastern``".
@@ -137,7 +141,9 @@ conventions when outputting the distinct ``restaurant`` values:
    const options = { collation: { locale: "de" }};
 
    const cursor = myColl.distinct("restaurant", query, options);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+     console.dir(doc);
+   }
 
 In this case, German string ordering conventions place words beginning with "Ä" before
 those beginning with "B". The code outputs the following:

source/fundamentals/crud/read-operations/limit.txt

@@ -42,7 +42,7 @@ snippet to insert documents that describe books into the
      { "_id": 3, "name": "Atlas Shrugged", "author": "Rand", "length": 1088 },
      { "_id": 4, "name": "Infinite Jest", "author": "Wallace", "length": 1104 },
      { "_id": 5, "name": "Cryptonomicon", "author": "Stephenson", "length": 918 },
-     { "_id": 6, "name": "A Dance With Dragons", "author": "Tolkein", "length": 1104 },
+     { "_id": 6, "name": "A Dance With Dragons", "author": "Martin", "length": 1104 },
    ]);
 
 .. include:: /includes/access-cursor-note.rst
@@ -64,7 +64,9 @@ books, and applies a ``limit`` to return only ``3`` results:
    const sort = { length: -1 };
    const limit = 3;
    const cursor = myColl.find(query).sort(sort).limit(limit);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+       console.dir;
+   }
 
 The code example above outputs the following three documents, sorted by
 length:
@@ -116,7 +118,9 @@ passing the number of documents to bypass as shown below:
    const limit = 3;
    const skip = 3;
    const cursor = myColl.find(query).sort(sort).limit(limit).skip(skip);
-   await cursor.forEach(console.dir);
+   for await (const doc of cursor) {
+       console.dir;
+   }
 
 This operation returns the documents that describe the fourth through sixth
 books in order of longest-to-shortest length: