Reads a file, re-reading until two reads spaced STABILITY_GAP_MS apart return byte-identical content — so a file caught mid-write (Windows truncate→flush; see STABILITY_GAP_MS) is hashed only once its bytes have settled. Bounded by MAX_STABILITY_ATTEMPTS; returns the latest content if it never stabilizes. read is injectable for tests; production reads from disk. Read errors propagate so the caller's catch can treat a vanished file as a removal.

import * as FileWatcher from './file-watcher.ts';

import { Buffer } from 'node:buffer';

const content = await FileWatcher.readFileStable('/proj/test/cart-test.ts', async () => Buffer.from('settled'));
content.toString(); // 'settled' — two reads 10ms apart returned identical bytes