Read and write OWLF

Validate OWLF files and convert app exports in the browser, in React Native or in Node.

npm install @owlf/core @owlf/adapters

Convert an export

import { detectAdapters } from "@owlf/adapters";
import { fileFromBlob, stringifyDocument } from "@owlf/core";

const files = [fileFromBlob(droppedFile)]; // a browser File
const [best] = await detectAdapters(files); // [{ adapter, score }], best first
const document = await best.adapter.parse(files);

const text = stringifyDocument(document); // data.owlf.json

Need one app only? Install its package, e.g. @owlf/adapter-daylio, and call daylio.parse(files).

Validate a file

import { parseDocument, validateDocument } from "@owlf/core";

const result = validateDocument(JSON.parse(text));
if (!result.ok) {
  console.log(result.issues); // [{ path: "entries.3.mood.level", message: "Unknown level \"x\"" }]
}

const document = parseDocument(text); // throws with the first issues when invalid

validateDocument checks the schema plus what JSON Schema cannot: level references, real calendar dates, zoneless only with an instant.

Runtimes

• Browser and React Native: every package’s main entry. No Node APIs, no network requests.
• Node 22+: ESM and require().
• @owlf/core/testkit: Node and Bun only, it reads fixtures from disk.