| 362 | * @returns {FnWithKey<T, R> & { force: FnWithKey<T, R> }} cached function |
| 363 | */ |
| 364 | const cachedWithKey = (fn, forceFn = fn) => { |
| 365 | /** |
| 366 | * Defines the cache entry type used by this module. |
| 367 | * @template R |
| 368 | * @typedef {{ result?: R, error?: Error, callbacks?: FnWithKeyCallback<R>[], force?: true }} CacheEntry |
| 369 | */ |
| 370 | /** @type {Map<T, CacheEntry<R>>} */ |
| 371 | const cache = new Map(); |
| 372 | /** |
| 373 | * Processes the provided arg. |
| 374 | * @param {T} arg arg |
| 375 | * @param {FnWithKeyCallback<R>} callback callback |
| 376 | * @returns {void} |
| 377 | */ |
| 378 | const resultFn = (arg, callback) => { |
| 379 | const cacheEntry = cache.get(arg); |
| 380 | if (cacheEntry !== undefined) { |
| 381 | if (cacheEntry.result !== undefined) { |
| 382 | return callback(null, cacheEntry.result); |
| 383 | } |
| 384 | if (cacheEntry.error !== undefined) return callback(cacheEntry.error); |
| 385 | if (cacheEntry.callbacks === undefined) cacheEntry.callbacks = [callback]; |
| 386 | else cacheEntry.callbacks.push(callback); |
| 387 | return; |
| 388 | } |
| 389 | /** @type {CacheEntry<R>} */ |
| 390 | const newCacheEntry = { |
| 391 | result: undefined, |
| 392 | error: undefined, |
| 393 | callbacks: undefined |
| 394 | }; |
| 395 | cache.set(arg, newCacheEntry); |
| 396 | fn(arg, (err, result) => { |
| 397 | if (err) newCacheEntry.error = err; |
| 398 | else newCacheEntry.result = result; |
| 399 | const callbacks = newCacheEntry.callbacks; |
| 400 | newCacheEntry.callbacks = undefined; |
| 401 | callback(err, result); |
| 402 | if (callbacks !== undefined) for (const cb of callbacks) cb(err, result); |
| 403 | }); |
| 404 | }; |
| 405 | /** |
| 406 | * Processes the provided arg. |
| 407 | * @param {T} arg arg |
| 408 | * @param {FnWithKeyCallback<R>} callback callback |
| 409 | * @returns {void} |
| 410 | */ |
| 411 | resultFn.force = (arg, callback) => { |
| 412 | const cacheEntry = cache.get(arg); |
| 413 | if (cacheEntry !== undefined && cacheEntry.force) { |
| 414 | if (cacheEntry.result !== undefined) { |
| 415 | return callback(null, cacheEntry.result); |
| 416 | } |
| 417 | if (cacheEntry.error !== undefined) return callback(cacheEntry.error); |
| 418 | if (cacheEntry.callbacks === undefined) cacheEntry.callbacks = [callback]; |
| 419 | else cacheEntry.callbacks.push(callback); |
| 420 | return; |
| 421 | } |