Add non-speciifc ensureIndex

Fixes #778.

CHANGELOG.md

@@ -18,7 +18,7 @@ This driver uses semantic versioning:
 
 ### Changed
 
-- Split the Collection type parameter into result and input types [#807](https://github.com/arangodb/arangojs/issues/807)
+- Split the Collection type parameter into result and input types ([#807](https://github.com/arangodb/arangojs/issues/807))
 
   It is now possible to specify a separate type for the data passed when
   creating or modifying documents in addition to the type of the data returned
@@ -31,6 +31,11 @@ This driver uses semantic versioning:
 
   This option was introduced in 3.12.1 and allows skipping the fast lock round.
 
+- Added non-specific `EnsureIndexOptions` type and `ensureIndex` method
+  signature ([#778](https://github.com/arangodb/arangojs/issues/778))
+
+  This allows creating indexes without narrowing the index type.
+
 ## [9.0.0-preview.4] - 2024-06-18
 
 ### Added

src/collection.ts

@@ -40,6 +40,7 @@ import {
   TtlIndex,
   MdiIndex,
   _indexHandle,
+  EnsureIndexOptions,
 } from "./indexes.js";
 import { COLLECTION_NOT_FOUND, DOCUMENT_NOT_FOUND } from "./lib/codes.js";
 
@@ -2006,6 +2007,27 @@ export interface DocumentCollection<
   ensureIndex(
     details: EnsureInvertedIndexOptions
   ): Promise<ArangoApiResponse<InvertedIndex & { isNewlyCreated: boolean }>>;
+  /**
+   * Creates an index on the collection if it does not already exist.
+   *
+   * @param details - Options for creating the index.
+   *
+   * @example
+   * ```js
+   * const db = new Database();
+   * const collection = db.collection("some-collection");
+   * // Create a unique index for looking up documents by username
+   * await collection.ensureIndex({
+   *   type: "persistent",
+   *   fields: ["username"],
+   *   name: "unique-usernames",
+   *   unique: true
+   * });
+   * ```
+   */
+  ensureIndex(
+    details: EnsureIndexOptions
+  ): Promise<ArangoApiResponse<Index & { isNewlyCreated: boolean }>>;
   /**
    * Deletes the index with the given name or `id` from the database.
    *

src/indexes.ts

@@ -518,6 +518,16 @@ export type EnsureInvertedIndexOptions = {
   optimizeTopK?: string[];
 };
 
+/**
+ * Options for creating an index.
+ */
+export type EnsureIndexOptions =
+  | EnsurePersistentIndexOptions
+  | EnsureGeoIndexOptions
+  | EnsureTtlIndexOptions
+  | EnsureMdiIndexOptions
+  | EnsureInvertedIndexOptions;
+
 /**
  * Shared attributes of all index types.
  */