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MongoDB API Reference

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mongodb.db()

Gets a handle for a database in a linked MongoDB data source.

const mongodb = context.services.get("mongodb-atlas");
const db = mongodb.db("myDB");
db(name: string): Database
Parameter
Type
Description
name
string
The name of the database.

The mongodb.db() method returns a Database object that allows you to access collections in the specified database.

See database.collection()

database.collection()

Gets a handle for a collection in a linked MongoDB data source from a database handle.

const mongodb = context.services.get("mongodb-atlas");
const db = mongodb.db("myDB");
const collection = db.collection("myCollection");
collection(name: string): Collection
Parameter
Type
Description
name
string
The name of the collection.

The database.collection() method returns a collection object that allows you to query the specified collection.

collection.find()

Finds all documents in a collection or view that match the provided query filters. Returns a cursor object that allows you to access matching documents.

const query = { "reviews.0": { "$exists": true } };
const projection = { "_id": 0 };
return itemsCollection.find(query, projection)
.sort({ name: 1 })
.toArray()
.then(items => {
console.log(`Successfully found ${items.length} documents.`)
items.forEach(console.log)
return items
})
.catch(err => console.error(`Failed to find documents: ${err}`))
find(
query?: object,
projection?: object,
options?: object
): Cursor
Parameter
Type
Description
query
object

Optional.

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

projection
object

Optional.

A document that specifies which fields MongoDB should include or omit in matching documents.

To return all fields in the matching documents, omit this parameter or specify an empty projection document ({}).

To return specific fields and the document's _id, specify the fields in the projection document with a value of 1:

// Includes the field in returned documents
{ <Field Name>: 1 }

To withhold specific fields, specify the fields in the projection document with a value of 0:

// Withholds the field from returned documents
{ <Field Name>: 0 }
Note

You may specify either fields to include or fields to withhold but not both. For example, the following projection is invalid because it simultaneously includes the name field and withholds the address field:

// Invalid
// Can't simultaneously include and withhold
{ "name": 1, "address": 0 }

The exception to this rule is the _id field, which you may withhold from any query:

// Valid
// Can exclude _id while including other fields
{ "_id": 0, "name": 1 }
options
object
An object that specifies additional configuration options.
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.find() method returns a cursor object that points to any documents that match the specified query. You can manipulate and access documents in the query result set with the following cursor methods:

Method
Description
cursor.next()

Iterates the cursor and returns a Promise that resolves to the next document in the cursor. If the cursor is exhausted, the promise resolves to undefined.

Example
collection.find().next()
.then(doc => console.log("next document", doc))
cursor.toArray()

Iterates the cursor to exhaustion and returns a Promise that resolves to an array that contains all of the iterated documents.

Example
collection.find().toArray()
.then(docs => console.log("all documents", docs))
cursor.skip(amount)

Specifies a number of matching documents to omit from the query result set. MongoDB omits documents from the result set in sort order until it has skipped the specified number. If the query also specifies a limit, skipped documents do not count towards the limit threshold.

Note

You cannot call this method after retrieving one or more documents using cursor.next() or cursor.toArray().

cursor.limit(limit)

Specifies the maximum number of documents to include in the query result set. If the result set contains more documents than the specified limit, the cursor will return documents in order up to the limit.

Note

You cannot call this method after retrieving one or more documents using cursor.next() or cursor.toArray().

cursor.sort(sort)

Sorts documents in the result set according to the sort filter. Sort documents specify one or more fields to sort on. The value of each field indicates whether MongoDB should sort it in ascending (1) or descending (-1) order. For more information, see cursor.sort.

Note

You cannot call this method after retrieving one or more documents using cursor.next() or cursor.toArray().

Example

The following sort document specifies that documents should be sorted first by age from highest to lowest. Once sorted by age, the result set should further be sorted by name in alphabetical order for each distinct age value.

{ age: -1, name: 1 }
Note

You cannot return a cursor from a function. Instead, evaluate the cursor using cursor.next() or cursor.toArray() and return the result.

collection.findOne()

Finds a single document from a collection or view. If multiple documents match the query, this returns the first matching document according to the query's sort order or natural order.

const query = { "quantity": { "$gte": 25 } };
const projection = {
"title": 1,
"quantity": 1,
}
return itemsCollection.findOne(query, projection)
.then(result => {
if(result) {
console.log(`Successfully found document: ${result}.`);
} else {
console.log("No document matches the provided query.");
}
return result;
})
.catch(err => console.error(`Failed to find document: ${err}`));
findOne(
query?: object,
projection?: object,
options?: object
): Promise<object | null>
Parameter
Type
Description
query
object

Optional.

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

projection
object

Optional.

A document that specifies which fields MongoDB should include or omit in matching documents.

To return all fields in the matching documents, omit this parameter or specify an empty projection document ({}).

To return specific fields and the document's _id, specify the fields in the projection document with a value of 1:

// Includes the field in returned documents
{ <Field Name>: 1 }

To withhold specific fields, specify the fields in the projection document with a value of 0:

// Withholds the field from returned documents
{ <Field Name>: 0 }
Note

You may specify either fields to include or fields to withhold but not both. For example, the following projection is invalid because it simultaneously includes the name field and withholds the address field:

// Invalid
// Can't simultaneously include and withhold
{ "name": 1, "address": 0 }

The exception to this rule is the _id field, which you may withhold from any query:

// Valid
// Can exclude _id while including other fields
{ "_id": 0, "name": 1 }
options
object
An object that specifies additional configuration options.
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.findOne() method returns a Promise that resolves to the first document in the collection that matches the query. If no documents match the specified query, the promise resolves to null.

Promise<object | null>
collection.findOneAndUpdate()

Updates a single document in a collection or view and returns the document in either its pre-update or post-update form.

Unlike collection.updateOne(), this action allows you to atomically find, modify, and return a document with the same command. This avoids the risk of other update operations changing the document between separate find and update operations.

// Find the document that describes "lego"
const query = { "name": "lego" };
// Set some fields in that document
const update = {
"$set": {
"name": "blocks",
"price": 20.99,
"category": "toys"
}
};
// Return the updated document instead of the original document
const options = { returnNewDocument: true };
return itemsCollection.findOneAndUpdate(query, update, options)
.then(updatedDocument => {
if(updatedDocument) {
console.log(`Successfully updated document: ${updatedDocument}.`)
} else {
console.log("No document matches the provided query.")
}
return updatedDocument
})
.catch(err => console.error(`Failed to find and update document: ${err}`))
findOneAndUpdate(
query: object,
update: object,
options?: object
): Promise<object | null>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

update
object

An update document that specifies modifications to perform using MongoDB update operators.

options
object
An object that specifies additional configuration options.
options.upsert
boolean

Optional. Default: false.

A boolean that, if true, indicates that MongoDB should insert a new document that matches the query when the query does not match any existing documents in the collection.

options.sort
boolean

Optional.

Specifies the query sort order. You can specify one or more fields to sort on where the value of each field indicates whether MongoDB should sort it in ascending (1) or descending (-1) order.

Example

The following sort document specifies that documents should be sorted first by age from highest to lowest. Once sorted by age, the result set should further be sorted by name in alphabetical order for each distinct age value.

{ age: -1, name: 1 }
options.projection
boolean

A document that specifies which fields MongoDB should include or omit in matching documents.

To return all fields in the matching documents, omit this parameter or specify an empty projection document ({}).

To return specific fields and the document's _id, specify the fields in the projection document with a value of 1:

// Includes the field in returned documents
{ <Field Name>: 1 }

To withhold specific fields, specify the fields in the projection document with a value of 0:

// Withholds the field from returned documents
{ <Field Name>: 0 }
Note

You may specify either fields to include or fields to withhold but not both. For example, the following projection is invalid because it simultaneously includes the name field and withholds the address field:

// Invalid
// Can't simultaneously include and withhold
{ "name": 1, "address": 0 }

The exception to this rule is the _id field, which you may withhold from any query:

// Valid
// Can exclude _id while including other fields
{ "_id": 0, "name": 1 }
options.returnNewDocument
boolean

Optional. Default: false.

If true, the method returns the modified document in its updated form instead of its original, pre-update form.

options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.findOneAndUpdate() method returns a Promise that resolves to a single document that the query overwrote. If no documents match the specified query, the promise resolves to null.

Promise<object | null>
Note

You can specify whether to return the pre-replacement or post-replacement version of the document by setting the value of options.returnNewDocument. By default, returnNewDocument is false, which indicates that the promise should resolve to the pre-update version of the document.

collection.findOneAndReplace()

Overwrites a single document in a collection or view and returns the document in either its pre-replacement or post-replacement form.

Unlike collection.updateOne(), this action allows you to atomically find, modify, and return a document with the same command. This avoids the risk of other update operations changing the document between separate find and update operations.

// Find the document that describes "lego"
const query = { "name": "lego" };
// Replace it with a new document
const replacement = {
"name": "blocks",
"price": 20.99,
"category": "toys"
};
// Return the original document as it was before being replaced
const options = { "returnNewDocument": false };
return itemsCollection.findOneAndReplace(query, replacement, options)
.then(replacedDocument => {
if(replacedDocument) {
console.log(`Successfully replaced the following document: ${replacedDocument}.`)
} else {
console.log("No document matches the provided query.")
}
return updatedDocument
})
.catch(err => console.error(`Failed to find and replace document: ${err}`))
findOneAndReplace(
query: object,
replacement: object,
options?: object
): Promise<object | null>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

replacement
object

A document that will replace the matching document. The replacement document cannot contain any MongoDB update operators.

options
object
An object that specifies additional configuration options.
options.upsert
boolean

Optional. Default: false.

A boolean that, if true, indicates that MongoDB should insert a new document that matches the query when the query does not match any existing documents in the collection.

options.sort
boolean

Optional.

Specifies the query sort order. You can specify one or more fields to sort on where the value of each field indicates whether MongoDB should sort it in ascending (1) or descending (-1) order.

Example

The following sort document specifies that documents should be sorted first by age from highest to lowest. Once sorted by age, the result set should further be sorted by name in alphabetical order for each distinct age value.

{ age: -1, name: 1 }
options.projection
boolean

A document that specifies which fields MongoDB should include or omit in matching documents.

To return all fields in the matching documents, omit this parameter or specify an empty projection document ({}).

To return specific fields and the document's _id, specify the fields in the projection document with a value of 1:

// Includes the field in returned documents
{ <Field Name>: 1 }

To withhold specific fields, specify the fields in the projection document with a value of 0:

// Withholds the field from returned documents
{ <Field Name>: 0 }
Note

You may specify either fields to include or fields to withhold but not both. For example, the following projection is invalid because it simultaneously includes the name field and withholds the address field:

// Invalid
// Can't simultaneously include and withhold
{ "name": 1, "address": 0 }

The exception to this rule is the _id field, which you may withhold from any query:

// Valid
// Can exclude _id while including other fields
{ "_id": 0, "name": 1 }
options.returnNewDocument
boolean

Optional. Default: false.

If true, the method returns the modified document in its updated form instead of its original, pre-update form.

options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.findOneAndReplace() method returns a Promise that resolves to a single document that the query overwrote. If no documents match the specified query, the promise resolves to null.

Promise<object | null>
Note

You can specify whether to return the pre-replacement or post-replacement version of the document by setting the value of options.returnNewDocument. By default, returnNewDocument is false, which indicates that the promise should resolve to the pre-update version of the document.

collection.findOneAndDelete()

Removes a single document from a collection and returns the deleted document as it was immediately before it was deleted.

Unlike collection.updateOne(), this action allows you to atomically find, modify, and return a document with the same command. This avoids the risk of other update operations changing the document between separate find and update operations.

// Find the first document that has a quantity greater than 25
const query = { "quantity": { "$gte": 25 } };
// Sort the documents in order of descending quantity before
// deleting the first one.
const options = {
"sort": { "quantity": -1 }
}
return itemsCollection.findOneAndDelete(query, options)
.then(deletedDocument => {
if(deletedDocument) {
console.log(`Successfully deleted document that had the form: ${deletedDocument}.`)
} else {
console.log("No document matches the provided query.")
}
return deletedDocument
})
.catch(err => console.error(`Failed to find and delete document: ${err}`))
findOneAndDelete(
query: object,
options?: object
): Promise<object | null>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

options
object
An object that specifies additional configuration options.
options.sort
boolean

Optional.

Specifies the query sort order. You can specify one or more fields to sort on where the value of each field indicates whether MongoDB should sort it in ascending (1) or descending (-1) order.

Example

The following sort document specifies that documents should be sorted first by age from highest to lowest. Once sorted by age, the result set should further be sorted by name in alphabetical order for each distinct age value.

{ age: -1, name: 1 }
options.projection
boolean

A document that specifies which fields MongoDB should include or omit in matching documents.

To return all fields in the matching documents, omit this parameter or specify an empty projection document ({}).

To return specific fields and the document's _id, specify the fields in the projection document with a value of 1:

// Includes the field in returned documents
{ <Field Name>: 1 }

To withhold specific fields, specify the fields in the projection document with a value of 0:

// Withholds the field from returned documents
{ <Field Name>: 0 }
Note

You may specify either fields to include or fields to withhold but not both. For example, the following projection is invalid because it simultaneously includes the name field and withholds the address field:

// Invalid
// Can't simultaneously include and withhold
{ "name": 1, "address": 0 }

The exception to this rule is the _id field, which you may withhold from any query:

// Valid
// Can exclude _id while including other fields
{ "_id": 0, "name": 1 }
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.findOneAndDelete() method returns a Promise that resolves to a single document that the query deleted. If no documents match the specified query, the promise resolves to null.

Promise<object | null>
collection.insertOne()

Inserts a single document into a collection and returns the _id of the inserted document.

const newItem = {
"name": "Plastic Bricks",
"quantity": 10,
"category": "toys",
"reviews": [{ "username": "legolover", "comment": "These are awesome!" }]
};
itemsCollection.insertOne(newItem)
.then(result => console.log(`Successfully inserted item with _id: ${result.insertedId}`))
.catch(err => console.error(`Failed to insert item: ${err}`))
insertOne(document: object): Promise<object>
Parameter
Type
Description
document
object
A document to insert into the collection.

The collection.insertOne() method returns a Promise that resolves to a document that describes the insert operation.

Promise<object>
Value
Type
Description
result.insertedId
string
The _id value of the document that the insert operation added to the collection.
collection.insertMany()

Inserts one or more documents into a collection and returns a list that contains the _id value for each inserted document.

const doc1 = { "name": "basketball", "category": "sports", "quantity": 20, "reviews": [] };
const doc2 = { "name": "football", "category": "sports", "quantity": 30, "reviews": [] };
return itemsCollection.insertMany([doc1, doc2])
.then(result => {
console.log(`Successfully inserted ${result.insertedIds.length} items!`);
return result
})
.catch(err => console.error(`Failed to insert documents: ${err}`))
insertMany(documents: object[]): Promise<object>
Parameter
Type
Description
documents
object
An array of documents to insert into the collection.

The collection.insertMany() method returns a Promise that resolves to a document that describes the insert operation.

Promise<object>
Value
Type
Description
result.insertedIds: Array<ObjectID>
string
An array that contains the _id values for all documents that the insert operation added to the collection in the order that they were passed to the method.
collection.updateOne()

Updates a single document in a collection and returns metadata about the operation.

const query = { "name": "football" };
const update = {
"$push": {
"reviews": {
"username": "tombradyfan",
"comment": "I love football!!!"
}
}
};
const options = { "upsert": false };
itemsCollection.updateOne(query, update, options)
.then(result => {
const { matchedCount, modifiedCount } = result;
if(matchedCount && modifiedCount) {
console.log(`Successfully added a new review.`)
}
})
.catch(err => console.error(`Failed to add review: ${err}`))
updateOne(
query: object,
update: object,
options?: object
): Promise<object>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

update
object

An update document that specifies modifications to perform using MongoDB update operators.

options
object
An object that specifies additional configuration options.
options.upsert
boolean

Optional. Default: false.

A boolean that, if true, indicates that MongoDB should insert a new document that matches the query when the query does not match any existing documents in the collection.

options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.updateOne() method returns a Promise that resolves to a document that describes the update operation.

Promise<object>
Value
Type
Description
result.matchedCount
number
The number of documents in the collection that match the provided query.
result.modifiedCount
number
The number of documents in the collection that were modified by the update operation.
result.upsertedId
string
The _id value of the document inserted by an upsert operation. This value is only present when the upsert option is enabled and the update query does not match any documents.
collection.updateMany()

Updates one or more documents in a collection and returns metadata about the operation.

const query = {};
const update = { "$mul": { "quantity": 10 } };
const options = { "upsert": false }
return itemsCollection.updateMany(query, update, options)
.then(result => {
const { matchedCount, modifiedCount } = result;
console.log(`Successfully matched ${matchedCount} and modified ${modifiedCount} items.`)
return result
})
.catch(err => console.error(`Failed to update items: ${err}`))
updateMany(
query: object,
update: object,
options?: object
): Promise<object>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

update
object

An update document that specifies modifications to perform using MongoDB update operators.

options
object
An object that specifies additional configuration options.
options.upsert
boolean

Optional. Default: false.

A boolean that, if true, indicates that MongoDB should insert a new document that matches the query when the query does not match any existing documents in the collection.

options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.updateMany() method returns a Promise that resolves to a document that describes the update operation.

Promise<object>
Value
Type
Description
result.matchedCount
number
The number of documents in the collection that match the provided query.
result.modifiedCount
number
The number of documents in the collection that were modified by the update operation.
result.upsertedId
string
The _id value of the document inserted by an upsert operation. This value is only present when the upsert option is enabled and the update query does not match any documents.
collection.deleteOne()

Removes a single document from a collection.

const query = { "name": "lego" };
itemsCollection.deleteOne(query)
.then(result => console.log(`Deleted ${result.deletedCount} item.`))
.catch(err => console.error(`Delete failed with error: ${err}`))
deleteOne(
query: object,
options?: object
): Promise<object>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

options
object
An object that specifies additional configuration options.
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.deleteOne() method returns a Promise that resolves to a document that describes the delete operation.

Promise<object>
Value
Type
Description
result.deletedCount
number
The number of documents in the collection that were deleted by the delete operation.
collection.deleteMany()

Remove one or more documents from a collection.

const query = { "reviews": { "$size": 0 } };
itemsCollection.deleteMany(query)
.then(result => console.log(`Deleted ${result.deletedCount} item(s).`))
.catch(err => console.error(`Delete failed with error: ${err}`))
deleteMany(
query: object,
options?: object
): Promise<object>
Parameter
Type
Description
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

options
object
An object that specifies additional configuration options.
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.deleteMany() method returns a Promise that resolves to a document that describes the delete operation.

Promise<object>
Value
Type
Description
result.deletedCount
number
The number of documents in the collection that were deleted by the delete operation.
collection.aggregate()

Executes an aggregation pipeline and returns a cursor that allows you to access the pipeline's output documents.

const pipeline = [
{ "$group": {
"_id": "$customerId",
"numPurchases": { "$sum": 1 },
"numItemsPurchased": { "$sum": { "$size": "$items" } }
} },
{ "$addFields": {
"averageNumItemsPurchased": {
"$divide": ["$numItemsPurchased", "$numPurchases"]
}
} }
]
return purchasesCollection.aggregate(pipeline).toArray()
.then(customers => {
console.log(`Successfully grouped purchases for ${customers.length} customers.`)
for(const customer of customers) {
console.log(`customer: ${customer._id}`)
console.log(`num purchases: ${customer.numPurchases}`)
console.log(`total items purchased: ${customer.numItemsPurchased}`)
console.log(`average items per purchase: ${customer.averageNumItemsPurchased}`)
}
return customers
})
.catch(err => console.error(`Failed to group purchases by customer: ${err}`))
aggregate(
pipeline: object[],
options?: object
): Cursor
Parameter
Type
Description
pipeline
object[]

An array of one or more aggregation pipeline stages.

Note
Supported Aggregation Stages

MongoDB Realm supports nearly all MongoDB aggregation pipeline stages and operators, but some stages and operators must be executed within a system function. See Aggregation Framework Limitations for more information.

options
object
An object that specifies additional configuration options.
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.aggregate() method returns a cursor object that points to any documents output from the final stage of the aggregation pipeline. You can manipulate and access documents in the aggregation result set with the following methods:

Method
Description
cursor.next()

Iterates the cursor and returns a Promise that resolves to the next document in the cursor. If the cursor is exhausted, the promise resolves to undefined.

Example
collection.aggregate(pipeline).next()
.then(doc => console.log("next document", doc))
cursor.toArray()

Iterates the cursor to exhaustion and returns a Promise that resolves to an array that contains all of the iterated documents.

Example
collection.aggregate(pipeline).toArray()
.then(docs => console.log("all documents", docs))
cursor.skip(amount)

Specifies a number of matching documents to omit from the aggregation result set. MongoDB omits documents from the result set in sort order until it has skipped the specified number.

Note

You cannot call this method after retrieving one or more documents using cursor.next() or cursor.toArray().

Note

You cannot return a cursor from a function. Instead, evaluate the cursor using cursor.next() or cursor.toArray() and return the result.

collection.count()

Returns the number of documents in a collection or view that match a given query.

return itemsCollection.count({ "reviews.0": { "$exists": true } })
.then(numDocs => console.log(`${numDocs} items have a review.`))
.catch(err => console.error("Failed to count documents: ", err))
count(
query?: object,
options?: object
): Promise<number>
Parameter
Type
Description
query
object

Optional.

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

options
object
An object that specifies additional configuration options.
options.session
ClientSession
Optional. A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.count() method returns a Promise that resolves to the integer number of documents in the collection that match the query.

Promise<number>
Value
Description

Count Result

numDocs: <integer>
The number of documents in the collection that match the provided query.
collection.distinct()

Finds documents that match a given query filter and returns a list of distinct values for a specific field across all matched documents.

1const taskCollection = context.services.get("mongodb-atlas")
2 .db("tracker").collection("tasks");
3
4return taskCollection.distinct("status", {})
5 .then(results => {
6 console.log(JSON.stringify(results));
7 console.log(results.length);
8 })
9 .catch(err => console.error(err))
distinct(
field: string,
query: object,
options?: object
): Promise<any[]>
Parameter
Type
Description
field
string
The name of the field in each document from which to find distinct values.
query
object

A query filter that specifies which documents to find. Specify an empty query ({}) or omit this parameter to match all documents in the collection.

You can use most query selectors except for evaluation, geospatial, or bitwise selectors.

options
object
An object that specifies additional configuration options.
options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.distinct() method returns a Promise that resolves to an array of distinct values.

Promise<any[]>
collection.bulkWrite()

Runs multiple insert, update, and delete operations on a collection with a single call. Within the bulkWrite() function, you can specify one or more of the following write operations:

  • insertOne
  • updateOne
  • updateMany
  • deleteOne
  • deleteMany
  • replaceOne
Note

A bulk write can only operate on a single collection.

exports = async function(arg){
const doc1 = { "name": "velvet elvis", "quantity": 20, "reviews": [] };
const doc2 = { "name": "mock turtleneck", "quantity": 30, "reviews": [] };
var collection = context.services.get("mongodb-atlas")
.db("store")
.collection("purchases");
return await collection.bulkWrite(
[{ insertOne: doc1}, { insertOne: doc2}],
{ordered:true});
};
bulkWrite(
operations: object[],
options?: object
): Promise<null>
Parameter
Type
Description
operations
object[]

An array of bulkWrite operations to perform. Examples of supported operations include the following:

{ insertOne: { document: { a: 1 } } }
{ updateOne: { filter: {a:2}, update: {$set: {a:2}}, upsert:true } }
{ updateMany: { filter: {a:2}, update: {$set: {a:2}}, upsert:true } }
{ deleteOne: { filter: {c:1} } }
{ deleteMany: { filter: {c:1} } }
{ replaceOne: { filter: {c:3}, replacement: {c:4}, upsert:true}}
options
object
An object that specifies additional configuration options.
options.ordered
boolean

Optional. Default: true.

If true, the operations are executed one at a time in the specified order (i.e. serially). If an error occurs while processing an ordered operation, the entire bulk operation returns without processing the remaining operations in the list.

If false, the operations are executed independently and may be processed in parallel. If an error occurs while processing an unordered operation, MongoDB continues to process remaining write operations in the list.

Note

Unordered operations are theoretically faster since MongoDB can execute them in parallel, but should only be used if the writes do not depend on order.

options.bypassDocumentValidation
boolean

Optional. Default: false.

If true, the operation bypasses schema validation in Realm.

options.session
ClientSession

Optional.

A session object that represents the transaction context in which the operation occurs. To learn more, see Transactions.

The collection.bulkWrite() function returns a Promise that resolves to null.

Promise<null>
←  Aggregate Data in MongoDB Atlas - FunctionsGlobal Modules →
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