mpackdb

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1. /**
2. * Cursor for iterating over query results
3. */
4. export class Cursor {
5. #db;
6. #queryFn;
7. #iterator;
8. #options;
10. /**
11. * Creates a new Cursor
12. * @param {MPackDB} db - The database instance
13. * @param {function} [queryFn] - Query function to filter records
14. * @param {Object} [options] - Query options
15. */
16. constructor(db, queryFn = () => true, options = {}) {
17. this.#db = db;
18. this.#queryFn = queryFn;
19. this.#options = options;
20. }
22. /**
23. * Makes the cursor awaitable (converts to array)
24. * @param {function} resolve - Promise resolve function
25. * @param {function} reject - Promise reject function
26. */
27. then(resolve, reject) {
28. // This makes the cursor "awaitable"
29. this.toArray().then(resolve, reject);
30. }
32. /**
33. * Async iterator implementation
34. * @yields {Object} Database records
35. */
36. async *[Symbol.asyncIterator]() {
37. if (!this.#iterator) {
38. this.#iterator = this.#db.recordGenerator(this.#queryFn, this.#options);
39. }
40. yield* this.#iterator;
41. }
43. /**
44. * Gets the next record from the cursor
45. * @returns {Promise<{value: Object, done: boolean}>} Iterator result
46. */
47. next() {
48. if (!this.#iterator) {
49. this.#iterator = this.#db.recordGenerator(this.#queryFn, this.#options);
50. }
51. return this.#iterator.next();
52. }
54. /**
55. * Converts the cursor results to an array
56. * @returns {Promise<Object[]>} Array of all matching records
57. */
58. async toArray() {
59. const results = [];
60. for await (const record of this) {
61. results.push(record);
62. }
63. return results;
64. }
65. }
67. export default Cursor;