@react-native-firebase/firestore/lib/FirestoreAggregate.js

React Native Firebase - Cloud Firestore is a NoSQL cloud database to store and sync data between your React Native application and Firebase's database. The API matches the Firebase Web SDK whilst taking advantage of the native SDKs performance and offline

/*
 * Copyright (c) 2022-present Invertase Limited & Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this library except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

import FirestoreFieldPath, { fromDotSeparatedString } from './FirestoreFieldPath';

export class FirestoreAggregateQuery {
  constructor(firestore, query, collectionPath, modifiers) {
    this._firestore = firestore;
    this._query = query;
    this._collectionPath = collectionPath;
    this._modifiers = modifiers;
  }

  get query() {
    return this._query;
  }

  get() {
    return this._firestore.native
      .collectionCount(
        this._collectionPath.relativeName,
        this._modifiers.type,
        this._modifiers.filters,
        this._modifiers.orders,
        this._modifiers.options,
      )
      .then(data => new FirestoreAggregateQuerySnapshot(this._query, data, true));
  }
}

export class FirestoreAggregateQuerySnapshot {
  constructor(query, data, isGetCountFromServer) {
    this._query = query;
    this._data = data;
    this._isGetCountFromServer = isGetCountFromServer;
  }

  data() {
    if (this._isGetCountFromServer) {
      return { count: this._data.count };
    } else {
      return { ...this._data };
    }
  }
}

export const AggregateType = {
  SUM: 'sum',
  AVG: 'average',
  COUNT: 'count',
};

export class AggregateField {
  /** Indicates the aggregation operation of this AggregateField. */
  aggregateType;
  _fieldPath;

  /**
   * Create a new AggregateField<T>
   * @param aggregateType Specifies the type of aggregation operation to perform.
   * @param _fieldPath Optionally specifies the field that is aggregated.
   * @internal
   */
  constructor(aggregateType, fieldPath) {
    this.aggregateType = aggregateType;
    this._fieldPath = fieldPath;
  }
}

export function fieldPathFromArgument(path) {
  if (path instanceof FirestoreFieldPath) {
    return path;
  } else if (typeof path === 'string') {
    return fromDotSeparatedString(path);
  } else {
    throw new Error('Field path arguments must be of type `string` or `FieldPath`');
  }
}