Node.js MongoDB Driver API

Class: ChangeStream

ChangeStream

new ChangeStream(parent, pipeline, options){ChangeStream}

lib/change_stream.js, line 53

Creates a new Change Stream instance. Normally created using Collection.watch().

Name Type Description
parent MongoClient | Db | Collection

The parent object that created this change stream
pipeline Array

An array of aggregation pipeline stages through which to pass change stream documents
options ChangeStreamOptions optional

Optional settings
Since:
  • 3.0.0
Fires:
Returns:
ChangeStream instance.

Members

resumeToken

Properties:
Name Type Description
resumeToken ResumeToken

The cached resume token that will be used to resume
after the most recently returned change.

Methods

close(callback){Promise}

lib/change_stream.js, line 178

Close the Change Stream

Name Type Description
callback ChangeStream~resultCallback optional

The result callback.
Returns:
Promise if no callback passed

hasNext(callback){Promise|void}

lib/change_stream.js, line 130

Check if there is any document still available in the Change Stream

Name Type Description
callback ChangeStream~resultCallback optional

The result callback.
Throws:
MongoError
Returns:
Promise if no callback passed

isClosed(){boolean}

lib/change_stream.js, line 169

Is the change stream closed

next(callback){Promise|void}

lib/change_stream.js, line 146

Get the next available document from the Change Stream, returns null if no more documents are available.

Name Type Description
callback ChangeStream~resultCallback optional

The result callback.
Throws:
MongoError
Returns:
Promise if no callback passed

pause(){null}

lib/change_stream.js, line 248

This method will cause a stream in flowing mode to stop emitting data events. Any data that becomes available will remain in the internal buffer.

pipe(destination, options){null}

lib/change_stream.js, line 212

This method pulls all the data out of a readable stream, and writes it to the supplied destination, automatically managing the flow so that the destination is not overwhelmed by a fast readable stream.

Name Type Description
destination Writable

The destination for writing data
options object optional

Pipe options

resume(){null}

lib/change_stream.js, line 256

This method will cause the readable stream to resume emitting data events.

stream(options){Cursor}

lib/change_stream.js, line 239

Return a modified Readable stream including a possible transform method.

Name Type Description
options object optional

Optional settings.

Name Type Description
transform function optional

A transformation method applied to each document emitted by the stream.

unpipe(destination){null}

lib/change_stream.js, line 225

This method will remove the hooks set up for a previous pipe() call.

Name Type Description
destination Writable optional

The destination for writing data

Type Definitions

resultCallback(error, result)

lib/change_stream.js, line 616

The callback format for results

Name Type Description
error MongoError

An error instance representing the error during the execution.
result object | null

The result object if the command was executed successfully.

Events

change

lib/change_stream.js, line 393

Fired for each new matching change in the specified namespace. Attaching a change
event listener to a Change Stream will switch the stream into flowing mode. Data will
then be passed as soon as it is available.

Type:
  • object

close

lib/change_stream.js, line 407

Change stream close event

Type:
  • null

end

lib/change_stream.js, line 414

Change stream end event

Type:
  • null

error

lib/change_stream.js, line 428

Fired when the stream encounters an error.

Type:
  • Error

resumeTokenChanged

lib/change_stream.js, line 421

Emitted each time the change stream stores a new resume token.

Type: