blob-storage

Blob Storage

Val Town provides built-in key/value blob storage via the std/blob module. Reach for it whenever a val needs to persist simple values — JSON documents, cached API responses, uploaded files, or binary assets — keyed by a string. For relational or structured data you query with SQL, prefer std/sqlite instead.

Scoping: account-global or per-val depending on import

There are two exports of the blob utility: global.ts, which is scoped to the user account, and main.ts, which is scoped to the val itself. Prefer the main.ts interface and val scoping for new vals.

Here is the scoped import:

/**
 * Importing from `main.ts` provides an interface to val-scoped blobs.
 */
import { blob } from "https://esm.town/v/std/blob/main.ts";

Here are the global imports:

/**
 * Importing from `global.ts` provides a blob interface that is scoped
 * to your account.
 */
import { blob } from "https://esm.town/v/std/blob/global.ts";
/**
 * This entrypoint is also available as `v/std/blob`. This is common
 * in older vals.
 */
import { blob } from "https://esm.town/v/std/blob";

The scoped & global blob interfaces have the same methods.

Scoped & global blobs are stored separately: you cannot access global blobs with the scoped interface or vice versa.

Basic usage (JSON)

import { blob } from "https://esm.town/v/std/blob/main.ts";

await blob.setJSON("config", { theme: "dark", count: 0 });

const config = await blob.getJSON("config");
// config = { theme: "dark", count: 0 }, or undefined if the key doesn't exist

getJSON returns undefined when the key is missing, so guard before using the result:

const config = (await blob.getJSON("config")) ?? { theme: "light", count: 0 };

Raw and binary data

Use set/get for strings, binary, or any BodyInit. get returns a standard Response, so use its body helpers (.text(), .json(), .arrayBuffer(), .blob()):

await blob.set("logo.png", imageBytes); // string | BodyInit (Blob, ArrayBuffer, ReadableStream, …)

const res = await blob.get("logo.png");
const bytes = await res.arrayBuffer();