Propagate getRange support in Listable when available

.changeset/rich-horses-count.md

@@ -0,0 +1,5 @@
+---
+"@zarrita/core": patch
+---
+
+Propagate getRange support in `Listable` when available

packages/core/__tests__/consolidated.test.ts

@@ -1,6 +1,6 @@
 import * as path from "node:path";
 import * as url from "node:url";
-import { describe, expect, it } from "vitest";
+import { assert, describe, expect, it } from "vitest";
 
 import { FileSystemStore } from "@zarrita/storage";
 import { tryWithConsolidated, withConsolidated } from "../src/consolidated.js";
@@ -124,3 +124,15 @@ describe("tryWithConsolidated", () => {
 		expect(store).toBeInstanceOf(FileSystemStore);
 	});
 });
+
+describe("Listable.getRange", () => {
+	it("does not expose getRange if the underlying store does not support it", async () => {
+		let store = await tryWithConsolidated(new Map());
+		expect("getRange" in store).toBeFalsy();
+	});
+	it("retrieves a byte range from an underlying store", async () => {
+		let root = path.join(__dirname, "../../../fixtures/v2/data.zarr");
+		let store = await tryWithConsolidated(new FileSystemStore(root));
+		assert(typeof store.getRange === "function");
+	});
+});

packages/core/src/consolidated.ts

@@ -24,7 +24,9 @@ type ConsolidatedMetadata = {
  */
 export interface Listable<Store extends Readable> {
 	/** Get the bytes at a given path. */
-	get: Store["get"];
+	get: (...args: Parameters<Store["get"]>) => Promise<Uint8Array | undefined>;
+	/** Get a byte range at a given path. */
+	getRange: Store["getRange"];
 	/** List the contents of the store. */
 	contents(): { path: AbsolutePath; kind: "array" | "group" }[];
 }
@@ -93,6 +95,7 @@ export async function withConsolidated<Store extends Readable>(
 	for (let [key, value] of Object.entries(v2_meta.metadata)) {
 		known_meta[`/${key}`] = value;
 	}
+
 	return {
 		async get(
 			...args: Parameters<Store["get"]>
@@ -108,6 +111,10 @@ export async function withConsolidated<Store extends Readable>(
 			}
 			return maybe_bytes;
 		},
+		// Delegate range requests to the underlying store.
+		// Note: Supporting range requests for consolidated metadata is possible
+		// but unlikely to be useful enough to justify the effort.
+		getRange: store.getRange?.bind(store),
 		contents(): { path: AbsolutePath; kind: "array" | "group" }[] {
 			let contents: { path: AbsolutePath; kind: "array" | "group" }[] = [];
 			for (let [key, value] of Object.entries(known_meta)) {