runOnSchemaChange.ts

import { AbstractPowerSyncDatabase, SQLWatchOptions } from './AbstractPowerSyncDatabase.js';

export function runOnSchemaChange(
  callback: (signal: AbortSignal) => void,
  db: AbstractPowerSyncDatabase,
  options?: SQLWatchOptions
): void {
  const triggerWatchedQuery = () => {
    const abortController = new AbortController();
    let disposeSchemaListener: (() => void) | null = null;
    const stopWatching = () => {
      abortController.abort('Abort triggered');
      disposeSchemaListener?.();
      disposeSchemaListener = null;
      // Stop listening to upstream abort for this watch
      options?.signal?.removeEventListener('abort', stopWatching);
    };

    options?.signal?.addEventListener('abort', stopWatching);
    disposeSchemaListener = db.registerListener({
      schemaChanged: async () => {
        stopWatching();
        // Re trigger the watched query (recursively), setTimeout ensures that we don't modify the list of listeners while iterating through them
        setTimeout(() => triggerWatchedQuery(), 0);
      }
    });
    callback(abortController.signal);
  };

  triggerWatchedQuery();
}