QueryPartition

new QueryPartition()

A split point that can be used in a query as a starting and/or end point for the query results. The cursors returned by #startAt and #endBefore can only be used in a query that matches the constraint of query that produced this partition.

Members

endBefore

The cursor that defines the first result after this partition or undefined if this is the last partition. The cursor value must be destructured when passed to endBefore() (for example with query.endBefore(...queryPartition.endBefore)).

Example

const query = firestore.collectionGroup('collectionId');
for await (const partition of query.getPartitions(42)) {
  let partitionedQuery = query.orderBy(FieldPath.documentId());
  if (partition.startAt) {
    partitionedQuery = partitionedQuery.startAt(...partition.startAt);
  }
  if (partition.endBefore) {
    partitionedQuery = partitionedQuery.endBefore(...partition.endBefore);
  }
  const querySnapshot = await partitionedQuery.get();
  console.log(`Partition contained ${querySnapshot.length} documents`);
}

startAt

The cursor that defines the first result for this partition or undefined if this is the first partition. The cursor value must be destructured when passed to startAt() (for example with query.startAt(...queryPartition.startAt)).

Example

const query = firestore.collectionGroup('collectionId');
for await (const partition of query.getPartitions(42)) {
  let partitionedQuery = query.orderBy(FieldPath.documentId());
  if (partition.startAt) {
    partitionedQuery = partitionedQuery.startAt(...partition.startAt);
  }
  if (partition.endBefore) {
    partitionedQuery = partitionedQuery.endBefore(...partition.endBefore);
  }
  const querySnapshot = await partitionedQuery.get();
  console.log(`Partition contained ${querySnapshot.length} documents`);
}

Methods

toQuery() → {Query.<T>}

Returns a query that only encapsulates the documents for this partition.

Returns:

Type	Description
Query.<T>	A query partitioned by a Query#startAt and Query#endBefore cursor.

Example

const query = firestore.collectionGroup('collectionId');
for await (const partition of query.getPartitions(42)) {
  const partitionedQuery = partition.toQuery();
  const querySnapshot = await partitionedQuery.get();
  console.log(`Partition contained ${querySnapshot.length} documents`);
}

QueryPartition

new QueryPartition()

Members

endBefore

Example

const query = firestore.collectionGroup('collectionId');
for await (const partition of query.getPartitions(42)) {
  let partitionedQuery = query.orderBy(FieldPath.documentId());
  if (partition.startAt) {
    partitionedQuery = partitionedQuery.startAt(...partition.startAt);
  }
  if (partition.endBefore) {
    partitionedQuery = partitionedQuery.endBefore(...partition.endBefore);
  }
  const querySnapshot = await partitionedQuery.get();
  console.log(`Partition contained ${querySnapshot.length} documents`);
}

startAt

Example

const query = firestore.collectionGroup('collectionId');
for await (const partition of query.getPartitions(42)) {
  let partitionedQuery = query.orderBy(FieldPath.documentId());
  if (partition.startAt) {
    partitionedQuery = partitionedQuery.startAt(...partition.startAt);
  }
  if (partition.endBefore) {
    partitionedQuery = partitionedQuery.endBefore(...partition.endBefore);
  }
  const querySnapshot = await partitionedQuery.get();
  console.log(`Partition contained ${querySnapshot.length} documents`);
}

Methods

toQuery() → {Query.<T>}

Returns a query that only encapsulates the documents for this partition.

Returns:

Type	Description
Query.<T>	A query partitioned by a Query#startAt and Query#endBefore cursor.

Example

const query = firestore.collectionGroup('collectionId');
for await (const partition of query.getPartitions(42)) {
  const partitionedQuery = partition.toQuery();
  const querySnapshot = await partitionedQuery.get();
  console.log(`Partition contained ${querySnapshot.length} documents`);
}