Find distinct values (TypeScript)
Finds the distinct values of a key for documents in a collection.
This method finds all documents that match the filter, or all documents if no filter is applied. There can be performance, latency, and billing implications if there are many matching documents.
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Ready to write code? See the examples for this method to get started. If you are new to the Data API, check out the quickstart. |
Result
Returns a promise that resolves to a list of the distinct values of the specified key. Documents that do not include the requested key are ignored.
The TypeScript client will attempt to infer the return type. However, you may need to explicitly cast the return type to match the expected type.
Example resolved response:
['home_appliance', None, 'sports_equipment', {'cat_id': 54, 'cat_name': 'gardening_gear'}]Parameters
Use the distinct method, which belongs to the Collection class.
Method signature
async distinct(
key: Key,
filter: CollectionFilter<Schema>,
options: {
timeout?: number | TimeoutDescriptor,
},
): Flatten<(SomeDoc & ToDotNotation<Schema>)[Key]>[]| Name | Type | Summary |
|---|---|---|
|
|
The name of the field for which to find values. See the examples for usage. |
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An object that defines filter criteria using the Data API filter syntax. The method only finds documents that match the filter criteria. Filters can improve performance by reducing the number of documents that the Data API processes. You must use For a list of available filter operators and more examples, see Filter operators for collections (TypeScript). Filters can use only indexed fields. If you apply selective indexing when you create a collection, you cannot reference non-indexed fields in a filter. For an example, see Find distinct values for a subset of documents. |
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Optional.
The options for this operation. See Properties of |
| Name | Type | Summary |
|---|---|---|
|
|
Optional. The timeout(s) to apply to this method.
You can specify For more information about the |
Examples
The following examples demonstrate how to find distinct values of a key for documents in a collection.
Find distinct values of a top level field
import {
DataAPIClient,
UsernamePasswordTokenProvider,
} from "@datastax/astra-db-ts";
// Get an existing collection
const client = new DataAPIClient({ environment: "hcd" });
const database = client.db("API_ENDPOINT", {
token: new UsernamePasswordTokenProvider("USERNAME", "PASSWORD"),
keyspace: "KEYSPACE_NAME",
});
const collection = database.collection("COLLECTION_NAME");
(async function () {
// Find distinct values
const result = await collection.distinct("publication_year", {});
console.log(result);
})();Find distinct values of a nested field
To find distinct values for a nested field, use dot notation.
For example, field.subfield.subsubfield.
You must use & to escape any literal . or & in field names.
import {
DataAPIClient,
UsernamePasswordTokenProvider,
} from "@datastax/astra-db-ts";
// Get an existing collection
const client = new DataAPIClient({ environment: "hcd" });
const database = client.db("API_ENDPOINT", {
token: new UsernamePasswordTokenProvider("USERNAME", "PASSWORD"),
keyspace: "KEYSPACE_NAME",
});
const collection = database.collection("COLLECTION_NAME");
(async function () {
// Find distinct values
const result = await collection.distinct("metadata.language", {});
console.log(result);
})();Find distinct values of an index in an array
To find distinct values for a specific index in an array, specify the index with dot notation.
For example, genres.0 finds distinct values of the first position of an array stored in the "genres" field.
If an array is encountered and no numeric index is specified, the method visits all items in the array.
import {
DataAPIClient,
UsernamePasswordTokenProvider,
} from "@datastax/astra-db-ts";
// Get an existing collection
const client = new DataAPIClient({ environment: "hcd" });
const database = client.db("API_ENDPOINT", {
token: new UsernamePasswordTokenProvider("USERNAME", "PASSWORD"),
keyspace: "KEYSPACE_NAME",
});
const collection = database.collection("COLLECTION_NAME");
(async function () {
// Find distinct values
const result = await collection.distinct("genres.2", {});
console.log(result);
})();Find distinct values for a subset of documents
You can use a filter to find distinct values across documents that match the filter.
For a list of available filter operators and more examples, see Filter operators for collections (TypeScript).
Filters can use only indexed fields. If you apply selective indexing when you create a collection, you cannot reference non-indexed fields in a filter.
import {
DataAPIClient,
UsernamePasswordTokenProvider,
} from "@datastax/astra-db-ts";
// Get an existing collection
const client = new DataAPIClient({ environment: "hcd" });
const database = client.db("API_ENDPOINT", {
token: new UsernamePasswordTokenProvider("USERNAME", "PASSWORD"),
keyspace: "KEYSPACE_NAME",
});
const collection = database.collection("COLLECTION_NAME");
(async function () {
// Find distinct values
const result = await collection.distinct("publication_year", {
$and: [{ is_checked_out: false }, { number_of_pages: { $lt: 300 } }],
});
console.log(result);
})();Client reference
For more information, see the client reference.
