++

---

-> Technical documentation <-

mongodb-pipeline-builder

mongodb-pipeline-builder is a pipeline builder for the db.collection.aggregate, the db.aggregate and the mongoose Model.aggregate methods.

• Simplify pipelines by making them more readable
• Pipelines are easier to edit.
• Pipeline stages appear in an array.
• Sequential stages for documents

All stages except the Out, Merge, GeoNear, ChangeStream, ChangeStreamSplitLargeEvent and Paging stages can appear multiple times in a pipeline.

---

npm package

npm i -S mongodb-pipeline-builder

---

News and Breaking changes between v3 and v4

PipelineBuilder:

• Renaming getPipeline() with build()
• Added new stages: ChangeStream, ChangeStreamSplitLargeEvent, Densify, Documents, Fill, ListLocalSessions, ListSampledQueries, ListSearchIndexes, SearchMeta, SetWindowFields and ShardedDataDistribution.
• Added the possibility to insert stages without validation.
• Checking for non-duplicable stages.

Helpers:

• Replacing the Payload suffix with Helper suffix
• Prefixed with the name of the pipeline stage where they should be used

Operators:

• Prefixed with the $ symbol
• Rename MapOperator to $Map

GetResult:

• To be used if no Paging stage is set
• Removing GetDocs method arguments
• Added new GetElement method to the response object

GetPagingResult:

• To be used exclusively with Paging stage.

Welcome generics! GetResult<Type> and GetPagingResult<Type> now offer the ability to type responses.

---

Usage:

Using require()

const PipelineBuilder = require("mongodb-pipeline-builder").PipelineBuilder;
const { LookupEqualityHelper, ProjectOnlyHelper, Field } = require('mongodb-pipeline-builder/helpers');
const { $LessThanEqual, $ArrayElementAt, $Equal, $Expression } = require('mongodb-pipeline-builder/operators');

Using import

import { PipelineBuilder } from 'mongodb-pipeline-builder';
import { LookupEqualityHelper, ProjectOnlyHelper, Field } from 'mongodb-pipeline-builder/helpers';
import { $LessThanEqual, $ArrayElementAt, $Equal, $Expression } from 'mongodb-pipeline-builder/operators';

---

Pagination example

const myNewPipeline = new PipelineBuilder( 'myPagination', { debug: true } )
    .Match( $Expression( $LessThanEqual( '$id', 20 ) ) )
    .Project( ProjectOnlyHelper( 'name', 'weight' ) )
    .Paging( 5, 3 ) // 5 per page, page 3
    .build();

is equivalent to

const myNewPipeline = [ {
    $facet: {
        docs: [
            { $match: { $expr: { $lte: ["$id", 20] } } },
            { $project: { _id: 0, name: 1, weight: 1 } },
            { $skip: 10 },
            { $limit: 5 }
        ],
        count: [
            { $match: { $expr: { $lte: ["$id", 20] } } },
            { $count: "totalElements" }
        ]
    }
} ];

---

No pagination example

const myNewPipeline = new PipelineBuilder( 'user-skills' )
    .Match( $Expression( $Equal( '$id', 123456 ) ) )
    .Lookup( LookupEqualityHelper( 'profiles', 'profile', 'id', 'profileId' ) )
    .Project( ProjectOnlyHelper( 'firstname', 'lastname', 'email' ) )
    .AddFields(
        Field( 'skills', $ArrayElementAt( '$profile.skills', 0 ) ),
        Field( 'availability', $ArrayElementAt( '$profile.availability', 0 ) )
    )
    .Unset( 'profile' )
    .build();

is equivalent to

const myNewPipeline = [
    { $match: { $expr: { $eq: ["$id", 123456] } } },
    { $lookup: { from: "profiles", as: "profile", localField: "id", foreignField: "profileId" } },
    { $project: { _id: 0, firstname: 1, lastname: 1, email: 1 } },
    { $addFields: {
        skills: { $arrayElemAt: ["$profile.skills", 0] },
        availability: { $arrayElemAt: ["$profile.availability", 0] }
    } },
    { $unset: "profile" }
];

---

GetResult method (No pagination)

GetResult<T>(): Promise<GetResultResponse<T>>

GetResult<T>() is an asynchronous method that provides a very easy way to use aggregation responses.

This method returns a GetResultResponse object that contains 3 methods:

• GetDocs(): T[] to get all the documents that match the request.
• GetElement(index: number | 'last'): T to get a particular document by its index.
• GetCount(): number to get the total number of documents found.

const result = await GetResult<DocType>( target, pipeline ); 
result.GetDocs(); // () => DocType[]
result.GetElement(index | 'last'); // () => DocType | undefined
result.GetCount(); // () => number

$Or

GetResult<DocType>( target, pipeline ).then( result => {
    result.GetDocs(); // () => DocType[]
    result.GetElement(index | 'last'); // () => DocType | undefined
    result.GetCount(); // () => number
} );

GetElement(index: number | 'last') method possibilities:

• A particular document can be retrieved by specifying its index.
• To get the last document, simply provide the string 'last'.
• If the specified index is greater than the index of the last document, GetElement() will return undefined.

// GetDocs() -> [document1, document2, document3, ..., document51]
result.GetElement(2); // will return document to index 2, document3
result.GetElement('last'); // will return the last document, document51
result.GetElement(99); // will return undefined

---

GetPagingResult method (Pagination)

GetPagingResult<T>(): Promise<GetPagingResultResponse<T>>

GetPagingResult<T>() is an asynchronous method that provides a very easy way to use aggregation responses when Paging stage is used.

This method returns a GetPagingResultResponse object that contains three methods:

• GetDocs() to get the documents found.
• GetCount() to get the total number of documents found.
• GetTotalPageNumber() to get the total number of pages.

const result = await GetPagingResult<DocType>(target, pipeline);
result.GetDocs(); // () => DocType[]
result.GetCount(); // () => number
result.GetTotalPageNumber(); // () => number

$Or

GetPagingResult<DocType>(target, pipeline).then( result => {
    result.GetDocs(); // () => DocType[]
    result.GetCount(); // () => number
    result.GetTotalPageNumber(); // () => number
} );

---

=> Try the lib on NPM RunKit with the require method <=

---

// builder = new PipelineBuilder('example');

CUSTOM STAGES

Paging(elementsPerPage, page)

The Paging stage automatically adds 3 native stages used to paginate documents ($skip, $limit and $count).
Page is optional and defaults to 1.

builder.Paging(5, 2).build();

// pipeline
[
  {
    $facet: {
      docs: [ { '$skip': 5 }, { '$limit': 5 } ],
      count: [ { '$count': 'totalElements' } ]
    }
  }
]

InsertStage(stage)

The InsertStage stage allows you to insert a stage without validation.
Usefully when you need to insert a stage that is not yet implemented or when the value fails validation but for some reason you want to keep it.

builder.InsertStage({ '$myCustomStage': { myField: 'myValue' } }).build();

// pipeline
[ { $myCustomStage: { myField: 'myValue' } } ]

MONGODB STAGES

AddFields(...values)

Helper: Field(name, value)

builder.AddFields(
  Field('foo', 'value1'),
  Field('bar', 'value2'),
).build();

// pipeline
[ { $addFields: { foo: 'value1', bar: 'value2' } } ]

Bucket(value)

Helper: BucketHelper(groupBy, boundaries, optional)

builder.Bucket(BucketHelper('$age', [6, 13, 18])).build();

// pipeline
[ { $bucket: { groupBy: '$age', boundaries: [ 6, 13, 18 ] } } ]

BucketAuto(value)

Helper: BucketAutoHelper(groupBy, buckets, optional)

builder.BucketAuto(BucketAutoHelper('$age', 5)).build();

// pipeline
[ { $bucketAuto: { groupBy: '$age', buckets: 5 } } ]

ChangeStream(value)

Helper: ChangeStreamHelper(optional)

builder.ChangeStream(ChangeStreamHelper()).build();

// pipeline
[ { $changeStream: {} } ]

ChangeStreamSplitLargeEvent()

builder.ChangeStreamSplitLargeEvent().build();

// pipeline
[ { $changeStreamSplitLargeEvent: {} } ]

CollStats(value)

Helper: CollStatsHelper(optional)

builder.CollStats(CollStatsHelper()).build();

// pipeline
[ { $collStats: {} } ]

Count(value)

builder.Count('counter').build();

// pipeline
[ { $count: 'counter' } ]

CurrentOp(value)

Helper: CurrentOpHelper(optional)

builder.CurrentOp(CurrentOpHelper()).build();

// pipeline
[ { $currentOp: {} } ]

Densify(value)

Helper: DensifyHelper(field, range, optional)

builder.Densify(
    DensifyHelper(
      'altitude',
      { bounds: 'full', step: 200 },
      { partitionByFields: [ 'variety' ] }
    ),
).build();

// pipeline
[
  {
    $densify: {
      field: 'altitude',
      range: { bounds: 'full', step: 200 }
      partitionByFields: [ 'variety' ],
    }
  }
]

Documents(...values)

builder.Documents({ doc1Id: 1 }, { doc2Id: 2 }, { doc3Id: 3 }).build();

// pipeline
[ { $documents: [ { doc1Id: 1 }, { doc2Id: 2 }, { doc3Id: 3 } ] } ]

Facet(...values)

Helper: Field(name, pipeline)

builder.Facet(
  Field('pipeline1', [{ $match: { tag: 'first' }}]),
  Field('pipeline2', [{ $match: { tag: 'second' }}]),
  Field('pipeline3', [{ $match: { tag: 'third' }}]),
).build();

// pipeline
[
  {
    $facet: {
      pipeline1: [ { '$match': { tag: 'first' } } ],
      pipeline2: [ { '$match': { tag: 'second' } } ],
      pipeline3: [ { '$match': { tag: 'third' } } ]
    }
  }
]

Fill(value)

Helper: FillHelper(output, optional)

builder.Fill(
  FillHelper({
    bootsSold: { value: 0 },
    sandalsSold: { value: 0 },
    sneakersSold: { value: 0 },
  }),
).build();

// pipeline
[
  {
    $fill: {
      output: {
        bootsSold: { value: 0 },
        sandalsSold: { value: 0 },
        sneakersSold: { value: 0 }
      }
    }
  }
]

GeoNear(value)

Helper: GeoNearHelper(near, distanceField, optional)

builder.GeoNear(
  GeoNearHelper({ type: "Point", coordinates: [ -73.99279 , 40.719296 ] }, 'calculated')
).build();

// pipeline
[
  {
    $geoNear: {
      near: { type: 'Point', coordinates: [ -73.99279, 40.719296 ] },
      distanceField: 'calculated'
    }
  }
]

GraphLookup(value)

builder.GraphLookup({
  from: 'employees', startWith: '$reportsTo', connectFromField: 'reportsTo', connectToField: 'name', as: 'reportingHierarchy',
}).build();

// pipeline
[
  {
    $graphLookup: {
      from: 'employees',
      startWith: '$reportsTo',
      connectFromField: 'reportsTo',
      connectToField: 'name',
      as: 'reportingHierarchy'
    }
  }
]

Group(value)

builder.Group({ _id: null, count: { $count: { } } }).build();

// pipeline
[
  { $group: { _id: null, count: { '$count': {} } } }
]

IndexStats()

builder.IndexStats().build();

// pipeline
[ { $indexStats: {} } ]

Limit(value)

builder.Limit(10).build();

// pipeline
[ { $limit: 10 } ]

ListLocalSessions(value)

builder.ListLocalSessions({ allUsers: true }).build();

// pipeline
[ { $listLocalSessions: { allUsers: true } } ]

ListSampledQueries(value)

builder.ListSampledQueries({ namespace: "social.post" }).build();

// pipeline
[ { $listSampledQueries: { namespace: 'social.post' } } ]

ListSearchIndexes(value)

builder.ListSearchIndexes({ name: 'searchIndex01' }).build();

// pipeline
[ { $listSearchIndexes: { name: 'searchIndex01' } } ]

ListSessions(value)

builder.ListSessions({ allUsers: true }).build();

// pipeline
[ { $listSessions: { allUsers: true } } ]

Lookup(value)

Helper: LookupConditionHelper(from, as, optional)

builder.Lookup(LookupConditionHelper('users', 'users')).build();

// pipeline
[ { $lookup: { from: 'users', as: 'users' } } ]

Helper: LookupEqualityHelper(from, as, localField, foreignField)

builder.Lookup(
  LookupEqualityHelper('users', 'users', 'userId', 'id')
).build();

// pipeline
[
  {
    $lookup: {
      from: 'users',
      localField: 'userId',
      foreignField: 'id',
      as: 'users'
    }
  }
]

Match(value)

Helper: Field(name, value)

builder.Match(Field('age', 18)).build();

// pipeline
[ { $match: { age: 18 } } ]

Operator: $Expression

builder.Match($Expression($GreaterThanEqual('$age', 18))).build();

// pipeline
[ { $match: { '$expr': { '$gte': [ '$age', 18 ] } } } ]

Merge(value)

Helper: MergeHelper(into, optional)

builder.Merge(MergeHelper('newCollection')).build();

// pipeline
[ { $merge: { into: 'newCollection' } } ]

Out(value)

Helper: OutHelper(collection, optional)

builder.Out(OutHelper('users')).build();

// pipeline
[ { $out: 'users' } ]

PlanCacheStats()

builder.PlanCacheStats().build();

// pipeline
[ { $planCacheStats: {} } ]

Project(...values)

Helper: ProjectHelper(field, value)

builder.Project(
  ProjectHelper('age', '$user.age'),
  ProjectHelper(
    'nickname',
    {
      $cond: {
        if: { $eq: [ '', '$user.nickname' ] },
        then: '$$REMOVE',
        else: '$user.nickname',
      },
    },
  ),
).build();

// pipeline
[
  {
    $project: {
      age: '$user.age',
      nickname: {
        $cond: {
          if: { $eq: [ '', '$user.nickname' ] },
          then: '$$REMOVE',
          else: '$user.nickname'
        }
      }
    }
  }
]

Helper: ProjectIgnoreHelper(...fields)

builder.Project(ProjectIgnoreHelper('password', 'refreshToken')).build();

// pipeline
[ { $project: { password: 0, refreshToken: 0 } } ]

Helper: ProjectOnlyHelper(...fields)

builder.Project(ProjectOnlyHelper('password', 'refreshToken')).build();

// pipeline
[ { $project: { _id: 0, password: 1, refreshToken: 1 } } ]

Redact(value)

builder.Redact(
  $Condition(
    $GreaterThan($Size($SetIntersection('$tags', ['STLW', 'G'])), 0),
    '$$DESCEND',
    '$$PRUNE'
  )
).build();

// pipeline
[
  {
    $redact: {
      '$cond': [
        { '$gt': [ { '$size': { '$setIntersection': [ '$tags', [ 'STLW', 'G' ] ] } }, 0 ] },
        '$$DESCEND',
        '$$PRUNE'
      ]
    }
  }
]

ReplaceRoot(value)

builder.ReplaceRoot({
  newRoot: { full_name: { $concat : [ "$first_name", " ", "$last_name" ] } }
}).build();

// pipeline
[
  {
    $replaceRoot: {
      newRoot: {
        full_name: { '$concat': [ '$first_name', ' ', '$last_name' ] }
      }
    }
  }
]

ReplaceWith(value)

builder.ReplaceWith('$name').build();

// pipeline
[ { $replaceWith: '$name' } ]

Sample(value)

Helper: SampleHelper(size)

builder.Sample(SampleHelper(6)).build();

// pipeline
[ { $sample: { size: 6 } } ]

Search(value)

Helper: SearchHelper(operator | collector, optional)

builder.Search(
  SearchHelper({
    near: { path: 'released', origin: date, pivot: 7776000000 },
  }),
).build();

// pipeline
[
  {
    $search: {
      near: { path: 'released', origin: date, pivot: 7776000000 },
    },
  }
]

SearchMeta(value)

Helper: SearchMetaHelper(collector, optional)

builder.SearchMeta(
  SearchMetaHelper({
    facet: {
      operator: {
        near: { path: 'released', origin: date, pivot: 7776000000 },
      },
      facets: {
        test: { type: 'number', path: 'released', boundaries: [0, 100] },
      },
    },
  })
).build();

// pipeline
[
  {
    $searchMeta: {
      facet: {
        operator: {
          near: { path: 'released', origin: date, pivot: 7776000000 },
        },
        facets: {
          test: { type: 'number', path: 'released', boundaries: [0, 100] },
        },
      },
    }
  }
]

Set(...values)

Helper: Field(name, value)

builder.Set(Field('first', true), Field('second', 2)).build();

// pipeline
[ { $set: { first: true, second: 2 } } ]

SetWindowFields(value)

builder.SetWindowFields({
  partitionBy: "$state",
  sortBy: { orderDate: 1 },
  output: {
    cumulativeQuantityForState: {
      $sum: "$quantity",
      window: { documents: [ "unbounded", "current" ] }
    }
  }
}).build();

// pipeline
[
  {
    $setWindowFields: {
      partitionBy: '$state',
      sortBy: { orderDate: 1 },
      output: {
        cumulativeQuantityForState: {
          '$sum': '$quantity',
          window: { documents: [ 'unbounded', 'current' ] }
        }
      }
    }
  }
]

ShardedDataDistribution(value)

builder.ShardedDataDistribution({}).build();

// pipeline
[ { $shardedDataDistribution: {} } ]

Skip(value)

builder.Skip(100).build();

// pipeline
[ { $skip: 100 } ]

Sort(...values)

Helper: Field(name, value)

builder.Sort(
  Field('first', -1),
  Field('second', 1),
  Field('third', { $meta: "textScore" }),
).build();

// pipeline
[
  {
    $sort: { first: -1, second: 1, third: { '$meta': 'textScore' } }
  }
]

SortByCount(value)

builder.SortByCount('$employee').build();
// pipeline

[ { $sortByCount: '$employee' } ]

UnionWith(value)

Helper: UnionWithHelper(collection, pipeline)

builder.UnionWith(
  UnionWithHelper('cars'),
).build();

// pipeline
[
  {
    $unionWith: { coll: 'cars' }
  }
]

builder.UnionWith(
  UnionWithHelper(
    undefined,
    [{ $document: [{ ref: 1 }, { ref: 2 }, { ref: 3 }],  }]),
).build();

// pipeline
[
  {
    $unionWith: { pipeline: [ { '$document': [ { ref: 1 }, { ref: 2 }, { ref: 3 } ] } ] }
  }
]

builder.UnionWith(
  UnionWithHelper('cars', [{ $match: { color: 'red' } }]),
).build();

// pipeline
[
  {
    $unionWith: { coll: 'cars', pipeline: [ { '$match': { color: 'red' } } ] }
  }
]

Unset(...values)

builder.Unset('users', 'roles').build();

// pipeline
[ { $unset: [ 'users', 'roles' ] } ]

Unwind(value)

builder.Unwind({ path: '$sizes', preserveNullAndEmptyArrays: true }).build();

// pipeline
[ { $unwind: { path: '$sizes', preserveNullAndEmptyArrays: true } } ]

---

MONGODB OPERATORS

$Absolute

$Absolute(-5)

// operator
{ $abs: -5 }

$Accumulator

$Accumulator(
  () => ({ count: 0, sum: 0 }),
  (state: { count: number; sum: number; }, numCopies: number) => ({
    count: state.count + 1,
    sum: state.sum + numCopies,
  }),
  ['$copies'],
  (state1: { count: number; sum: number; }, state2: { count: number; sum: number; }) => ({
    count: state1.count + state2.count,
    sum: state1.sum + state2.sum,
  }),
  { finalize: (state: { sum: number; count: number; }) => (state.sum / state.count) },
)

// operator
{
  '$accumulator': {
    init: [ () => ({ count: 0, sum: 0 }) ],
    accumulate: [
      (state: { count: number; sum: number; }, numCopies: number) => ({
        count: state.count + 1,
        sum: state.sum + numCopies,
      })
    ],
    accumulateArgs: [ '$copies' ],
    merge: [
      (state1: { count: number; sum: number; }, state2: { count: number; sum: number; }) => ({
        count: state1.count + state2.count,
        sum: state1.sum + state2.sum,
      })
    ],
    finalize: [ (state: { sum: number; count: number; }) => (state.sum / state.count) ],
    lang: 'js'
  }
}

$ArcCosine

$ArcCosine({ $divide : [ '$side_b', '$hypotenuse' ] })

// operator
{ '$acos': { '$divide': [ '$side_b', '$hypotenuse' ] } }

$ArcCosineHyperbolic

$ArcCosineHyperbolic(3)

// operator
{ '$acosh': 3 }

$Add

$Add('$price', 10)

// operator
{ '$add': [ '$price', 10 ] }

$AddToSet

$AddToSet('$item')

// operator
{ '$addToSet': '$item' }

$AllElementsTrue

$AllElementsTrue([ true, 1, "someString" ])

// operator
{ '$allElementsTrue': [ [ true, 1, 'someString' ] ] }

$And

$And(1, 'green')

// operator
{ '$and': [ 1, 'green' ] }

$AnyElementTrue

$AnyElementTrue([ true, false ])

// operator
{ '$anyElementTrue': [ [ true, false ] ] }

$ArrayElementAt

$ArrayElementAt([ 1, 2, 3 ], 0)

// operator
{ '$arrayElemAt': [ [ 1, 2, 3 ], 0 ] }

$ArrayToObject

$ArrayToObject([ { "k": "item", "v": "abc123" }, { "k": "qty", "v": "$qty" } ])

// operator
{ '$arrayToObject': [ { k: 'item', v: 'abc123' }, { k: 'qty', v: '$qty' } ] }

$ArrayToObject([ [ "item", "abc123" ], [ "qty", 25 ] ], true)              

// operator
{ '$arrayToObject': { '$literal': [ [ 'item', 'abc123' ], [ 'qty', 25 ] ] } }

$ArcSine

$ArcSine('$value')

// operator
{ '$asin': '$value' }

$ArcSineHyperbolic

$ArcSineHyperbolic('$value')

// operator
{ '$asinh': '$value' }

$ArcTangent

$ArcTangent('$value')

// operator
{ '$atan': '$value' }

$ArcTangent2

$ArcTangent2('$side_b', '$side_a')

// operator
{ '$atan2': [ '$side_b', '$side_a' ] }

$ArcTangentHyperbolic

$ArcTangentHyperbolic('$value')

// operator
{ '$atanh': '$value' }

$Average

$Average('$value')

// operator
{ '$avg': '$value' }

$Average('$value1', '$value2', '$value3')

// operator
{ '$avg': [ '$value1', '$value2', '$value3' ] }

$BinarySize

$BinarySize('Hello World!')

// operator
{ '$binarySize': 'Hello World!' }

$BitwiseAnd

$BitwiseAnd('$array')

// operator
{ '$bitAnd': '$array' }

$BitwiseAnd(0, 127, 5)

// operator
{ '$bitAnd': [ 0, 127, 5 ] }

$BitwiseNot

$BitwiseNot('$long')

// operator
{ '$bitNot': '$long' }

$BitwiseOr

$BitwiseOr('$array')

// operator
{ '$bitOr': '$array' }

$BitwiseOr(0, 127, 5)

// operator
{ '$bitOr': [ 0, 127, 5 ] }

$BitwiseXor

$BitwiseXor('$array')

// operator
{ '$bitXor': '$array' }

$BitwiseXor(0, 127, 5)

// operator
{ '$bitXor': [ 0, 127, 5 ] }

$Bottom

$Bottom(['field1', 'field2'], { field2: -1 })

// operator
{ '$bottom': { output: [ 'field1', 'field2' ], sortBy: { field2: -1 } } }

$BottomN

$BottomN('field', { field: 1 }, 3)

// operator
{ '$bottomN': { output: 'field', sortBy: { field: 1 }, n: 3 } }

$BsonSize

$BsonSize('$$ROOT')

// operator
{ '$bsonSize': '$$ROOT' }

$Ceil

$Ceil('$value')

// operator
{ '$ceil': '$value' }

$Compare

$Compare('$age', 25)

// operator
{ '$cmp': [ '$age', 25 ] }

$Concat

$Concat('$first', ' - ', '$second')

// operator
{ '$concat': [ '$first', ' - ', '$second' ] }

$ConcatArrays

$ConcatArrays('$array', [1, 2, 3])

// operator
{ '$concatArrays': [ '$array', [ 1, 2, 3 ] ] }

$Condition

$Condition({ $gte: [ '$quantity', 250 ] }, 'true', 'false')

// operator
{ '$cond': [ { '$gte': [ '$quantity', 250 ] }, 'true', 'false' ] }

$Convert

$Convert(100, 'bool')

// operator
{ '$convert': { input: 100, to: 'bool' } }

$Cosine

$Cosine('$angle')

// operator
{ '$cos': '$angle' }

$CosineHyperbolic

$CosineHyperbolic({ $degreesToRadians : "$angle" })

// operator
{ '$cosh': { '$degreesToRadians': '$angle' } }

$Count

$Count()

// operator
{ '$count': {} }

$CovariancePopulation

$CovariancePopulation('$numeric1', '$numeric2')

// operator
{ '$covariancePopulation': [ '$numeric1', '$numeric2' ] }

$CovarianceSample

$CovarianceSample('$numeric1', '$numeric2')

// operator
{ '$covarianceSample': [ '$numeric1', '$numeric2' ] }

$DateAdd

$DateAdd('$startDate', 'hour', 2)

// operator
{ '$dateAdd': { startDate: '$startDate', unit: 'hour', amount: 2 } }

$DateDifference

$DateDifference('$startDate', '$endDate', 'second')

// operator
{ '$dateDiff': { startDate: '$startDate', endDate: '$endDate', unit: 'second' } }

$DateFromParts

$DateFromCalendarParts(2000, { month: 12, day: 31, hour: 12, minute: 25, second: 59, timezone: '+01:00' })

// operator
{
  '$dateFromParts': {
    year: 2000,
    month: 12,
    day: 31,
    hour: 12,
    minute: 25,
    second: 59,
    timezone: '+01:00'
  }
}

$DateFromIsoWeekParts(2000, { isoWeek: 53, isoDayOfWeek: 7, millisecond: 500 })

// operator
{ '$dateFromParts': { isoWeekYear: 2000, isoWeek: 53, isoDayOfWeek: 7, millisecond: 500 } }

$DateFromString

$DateFromString('2017-02-08T12:10:40.787', { timezone: 'America/New_York' })

// operator
{
  '$dateFromString': {
    dateString: '2017-02-08T12:10:40.787',
    timezone: 'America/New_York'
  }
}

$DateSubtract

$DateSubtract(1697382106124, 'month', 1)

// operator
{ '$dateSubtract': { startDate: 1697382106124, unit: 'month', amount: 1 } }

$DateToParts

$DateToParts(1697382106124)

// operator
{ '$dateToParts': { date: 1697382106124 } }

$DateToString

$DateToString(1697382106124)

// operator
{ '$dateToString': { date: 1697382106124 } }

$DateTrunc

$DateTrunc(1697382106124, 'month')

// operator
{ '$dateTrunc': { date: 1697382106124, unit: 'month' } }

$DayOfMonth

$DayOfMonth('$date', 'Europe/Paris')

// operator
{ '$dayOfMonth': { date: '$date', timezone: 'Europe/Paris' } }

$DayOfWeek

$DayOfWeek('$date', '+03:30')

// operator
{ '$dayOfWeek': { date: '$date', timezone: '+03:30' } }

$DayOfYear

$DayOfYear('$date')

// operator
{ '$dayOfYear': { date: '$date' } }

$DegreesToRadians

$DegreesToRadians('$angle_a')

// operator
{ '$degreesToRadians': '$angle_a' }

$DenseRank

// operator

$Derivative

// operator

$Divide

// operator

$DocumentNumber

// operator

$Equal

// operator

$Exponent

// operator

$ExponentialMovingAverage

// operator

$Filter

// operator

$First

// operator

$FirstN

// operator

// operator

$Floor

// operator

$Function

// operator

$GetField

// operator

$GreaterThan

// operator

$GreaterThanEqual

// operator

$Hour

// operator

$IfNull

// operator

$In

// operator

$IndexOfArray

// operator

$IndexOfBytes

// operator

$IndexOfCodePoint

// operator

$Integral

// operator

$IsArray

// operator

$IsNumber

// operator

$IsoDayOfWeek

// operator

$IsoWeek

// operator

$IsoWeekYear

// operator

$Last

// operator

$LastN

// operator

// operator

$LessThan

// operator

$LessThanEqual

// operator

$Let

// operator

$Literal

// operator

$Log

// operator

$Log10

// operator

$Ltrim

// operator

$Map

// operator

$Max

// operator

$MergeObjects

// operator

$Meta

// operator

$Millisecond

// operator

$Min

// operator

$Minute

// operator

$Mod

// operator

$Month

// operator

$Multiply

// operator

$NaturalLog

// operator

$Not

// operator

$NotEqual

// operator

$ObjectToArray

// operator

$Or

// operator

$Pow

// operator

$Push

// operator

$RadiansToDegrees

// operator

$Rand

// operator

$Range

// operator

$Reduce

// operator

$RegexFind

// operator

$RegexFindAll

// operator

$RegexMatch

// operator

$ReplaceAll

// operator

$ReplaceOne

// operator

$ReverseArray

// operator

$Round

// operator

$Rtrim

// operator

$SampleRate

// operator

$Second

// operator

$SetDifference

// operator

$SetEquals

// operator

$SetIntersection

// operator

$SetIsSubset

// operator

$SetUnion

// operator

$Sin

// operator

$Sinh

// operator

$Size

// operator

$Slice

// operator

$Split

// operator

$Sqrt

// operator

$StdDevPop

// operator

$StdDevSamp

// operator

$StrCaseCmp

// operator

$StrLenBytes

// operator

$StrLenCP

// operator

$Substr

// operator

$SubstrBytes

// operator

$SubstrCP

// operator

$Subtract

// operator

$Sum

// operator

$Switch

// operator

$Tan

// operator

$Tanh

// operator

$ToBool

// operator

$ToDate

// operator

$ToDecimal

// operator

$ToDouble

// operator

$ToInt

// operator

$ToLong

// operator

$ToLower

// operator

$ToObjectId

// operator

$ToString

// operator

$ToUpper

// operator

$Trim

// operator

$Trunc

// operator

$Type

// operator

$Week

// operator

$Year

// operator

$Zip

// operator