CHANGELOG.md

   1 # Changelog
   2
   3 All notable changes to this project will be documented in this file.
   4
   5 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
   6 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   7
   8 ## [Unreleased]
   9
  10 ### Fixed
  11
  12 - Ensure unused worker usage statistics are deleted at runtime.
  13
  14 ### Changed
  15
  16 - Rename worker choice strategy options `choiceRetries` to `retries`.
  17 - Avoid unnecessary branching in worker choice strategies.
  18
  19 ## [2.6.36] - 2023-08-27
  20
  21 ### Fixed
  22
  23 - Fix pool `execute()` arguments check.
  24
  25 ### Changed
  26
  27 - Make continuous tasks stealing algorithm less aggressive.
  28 - Fine tune tasks stealing algorithm under back pressure.
  29
  30 ## [2.6.35] - 2023-08-25
  31
  32 ### Fixed
  33
  34 - Don't account worker usage statistics for tasks that have failed.
  35 - Fix pool information runtime and wait time median computation.
  36
  37 ### Changed
  38
  39 - Update simple moving average implementation to use a circular buffer.
  40 - Update simple moving median implementation to use a circular buffer.
  41 - Account for stolen tasks in worker usage statistics and pool information.
  42
  43 ### Added
  44
  45 - Continuous tasks stealing algorithm.
  46
  47 ## [2.6.34] - 2023-08-24
  48
  49 ### Fixes
  50
  51 - Avoid cascading tasks stealing under back pressure.
  52
  53 ### Changed
  54
  55 - Add fastpath to queued tasks rescheduling.
  56
  57 ## [2.6.33] - 2023-08-24
  58
  59 ### Fixed
  60
  61 - Fix queued tasks rescheduling.
  62
  63 ### Changed
  64
  65 - Rename tasks queue options `queueMaxSize` to `size`.
  66
  67 ### Added
  68
  69 - Task stealing scheduling algorithm if tasks queueing is enabled.
  70
  71 ## [2.6.32] - 2023-08-23
  72
  73 ### Fixed
  74
  75 - Ensure no task can be executed when the pool is destroyed.
  76
  77 ### Added
  78
  79 - Add `queueMaxSize` option to tasks queue options.
  80 - Add O(1) deque implementation implemented with doubly linked list and use it for tasks queueing.
  81 - Add tasks stealing algorithm when a worker node queue is back pressured if tasks queueing is enabled.
  82
  83 ## [2.6.31] - 2023-08-20
  84
  85 ### Fixed
  86
  87 - Fix worker choice strategy retries mechanism in some edge cases.
  88
  89 ### Changed
  90
  91 - Make orthogonal worker choice strategies tasks distribution and created dynamic worker usage.
  92 - Remove the experimental status of the `LEAST_ELU` worker choice strategy.
  93
  94 ## [2.6.30] - 2023-08-19
  95
  96 ### Fixed
  97
  98 - Ensure pool event `backPressure` is emitted.
  99 - Ensure pool event `full` is emitted only once.
 100 - Ensure worker node cannot be instantiated without proper arguments.
 101
 102 ## [2.6.29] - 2023-08-18
 103
 104 ### Fixed
 105
 106 - Fix race condition between ready and task functions worker message handling at startup.
 107 - Fix duplicate task function worker usage statistics computation per task function.
 108 - Update task function worker usage statistics if and only if there's at least two different task functions.
 109 - Fix race condition at task function worker usage executing task computation leading to negative value.
 110
 111 ### Added
 112
 113 - Add back pressure detection on the worker node queue. Event `backPressure` is emitted when all worker node queues are full (worker node queue size >= poolMaxSize^2).
 114 - Use back pressure detection in worker choice strategies.
 115 - Add worker choice strategies retries mechanism if no worker is eligible.
 116
 117 ## [2.6.28] - 2023-08-16
 118
 119 ### Fixed
 120
 121 - Ensure pool workers are properly initialized.
 122
 123 ### Added
 124
 125 - HTTP server pool examples: express-cluster, express-hybrid.
 126
 127 ### Changed
 128
 129 - Remove now useless branching in worker hot code path.
 130
 131 ## [2.6.27] - 2023-08-15
 132
 133 ### Fixed
 134
 135 - Add `KillHandler` type definition to exported types.
 136
 137 ### Added
 138
 139 - Add `destroy` event to pool API.
 140
 141 ## [2.6.26] - 2023-08-15
 142
 143 ### Added
 144
 145 - Add kill handler to worker options allowing to execute custom code when worker is killed.
 146 - Add `listTaskFunctions()` method to pool API.
 147 - SMTP server pool example: nodemailer.
 148
 149 ## [2.6.25] - 2023-08-13
 150
 151 ### Added
 152
 153 - HTTP server pool examples: fastify-cluster, fastify-hybrid.
 154 - WebSocket server pool examples: ws-cluster, ws-hybrid.
 155
 156 ## [2.6.24] - 2023-08-12
 157
 158 ### Added
 159
 160 - Add array of transferable objects to the `execute()` method arguments.
 161 - WebSocket server pool examples: ws-worker_threads.
 162
 163 ## [2.6.23] - 2023-08-11
 164
 165 ### Fixed
 166
 167 - Fix pool busyness semantic when tasks queueing is enabled: the pool is busy when the number of executing tasks on each worker has reached the maximum tasks concurrency per worker.
 168
 169 ### Added
 170
 171 - HTTP client pool examples: fetch, node-fetch and axios with multiple task functions.
 172 - HTTP server pool examples: express-worker_threads, fastify-worker_threads.
 173
 174 ## [2.6.22] - 2023-08-10
 175
 176 ### Fixed
 177
 178 - Add missing `types` field to package.json `exports`.
 179
 180 ### Changed
 181
 182 - Structure markdown documentation (PR #811).
 183
 184 ## [2.6.21] - 2023-08-03
 185
 186 ### Changed
 187
 188 - Improve code documentation.
 189 - Code refactoring and cleanup for better maintainability and readability.
 190
 191 ## [2.6.20] - 2023-07-21
 192
 193 ### Fixed
 194
 195 - Fix queued tasks redistribution on error task execution starvation.
 196 - Ensure tasks queueing per worker condition is untangled from the pool busyness semantic.
 197
 198 ### Changed
 199
 200 - Drastically reduce lookups by worker in the worker nodes.
 201
 202 ## [2.6.19] - 2023-07-20
 203
 204 ### Added
 205
 206 - Dedicated internal communication channel for worker_threads pools.
 207
 208 ## [2.6.18] - 2023-07-19
 209
 210 ### Changed
 211
 212 - Code refactoring and cleanup for better maintainability and readability. Bundle size is a bit smaller.
 213
 214 ## [2.6.17] - 2023-07-16
 215
 216 ### Added
 217
 218 - Add `listTaskFunctions()` method to worker API.
 219
 220 ## [2.6.16] - 2023-07-12
 221
 222 ### Fixed
 223
 224 - Fix pool startup detection.
 225 - Fix worker task functions handling.
 226
 227 ## [2.6.15] - 2023-07-11
 228
 229 ### Added
 230
 231 - Take into account worker node readiness in worker choice strategies.
 232
 233 ## [2.6.14] - 2023-07-10
 234
 235 ### Fixed
 236
 237 - Fix task function statistics tracking.
 238
 239 ## [2.6.13] - 2023-07-10
 240
 241 ### Added
 242
 243 - Add per task function statistics tracking.
 244 - Add public methods to manipulate the worker task functions at runtime.
 245
 246 ## [2.6.12] - 2023-07-09
 247
 248 ### Fixed
 249
 250 - Workaround import issue with `node:os` module in node 16.x.x.
 251
 252 ## [2.6.11] - 2023-07-09
 253
 254 ### Fixed
 255
 256 - Fix pool readiness semantic.
 257
 258 ## [2.6.10] - 2023-07-08
 259
 260 ### Fixed
 261
 262 - Ensure workers are not recreated on error at pool startup.
 263
 264 ### Added
 265
 266 - Add `ready` and `strategy` fields to pool information.
 267 - Add pool event `ready` to notify when the number of workers created in the pool has reached the maximum size expected and are ready.
 268 - Add dynamic pool sizing checks.
 269
 270 ## [2.6.9] - 2023-07-07
 271
 272 ### Fixed
 273
 274 - Recreate the right worker type on uncaught exception.
 275
 276 ### Added
 277
 278 - Add minimum and maximum to internal measurement statistics.
 279 - Add `runTime` and `waitTime` to pool information.
 280 - Check worker inactive time only on dynamic worker.
 281
 282 ## [2.6.8] - 2023-07-03
 283
 284 ### Fixed
 285
 286 - Brown paper bag release to fix version handling in pool information.
 287
 288 ## [2.6.7] - 2023-07-03
 289
 290 ### Fixed
 291
 292 - Ensure worker queued tasks at error are reassigned to other pool workers.
 293
 294 ### Added
 295
 296 - Add pool `utilization` ratio to pool information.
 297 - Add `version` to pool information.
 298 - Add worker information to worker nodes.
 299
 300 ## [2.6.6] - 2023-07-01
 301
 302 ### Added
 303
 304 - Add safe helper `availableParallelism()` to help sizing the pool.
 305
 306 ### Fixed
 307
 308 - Ensure message handler is only registered in worker.
 309
 310 ## [2.6.5] - 2023-06-27
 311
 312 ### Known issues
 313
 314 - Cluster pools tasks execution are not working by using ESM files extension: https://github.com/poolifier/poolifier/issues/782
 315
 316 ### Fixed
 317
 318 - Artificial version bump to 2.6.5 to workaround publication issue.
 319 - Ensure cluster pool `destroy()` gracefully shutdowns worker's server.
 320 - Ensure pool event is emitted before task error promise rejection.
 321 - Fix queued tasks count computation.
 322
 323 ### Removed
 324
 325 - Remove unneeded worker_threads worker `MessageChannel` internal usage for IPC.
 326
 327 ## [2.6.4] - 2023-06-27
 328
 329 ### Known issues
 330
 331 - Cluster pools tasks execution are not working by using ESM files extension: https://github.com/poolifier/poolifier/issues/782
 332
 333 ### Fixed
 334
 335 - Ensure cluster pool `destroy()` gracefully shutdowns worker's server.
 336 - Ensure pool event is emitted before task error promise rejection.
 337 - Fix queued tasks count computation.
 338
 339 ### Removed
 340
 341 - Remove unneeded worker_threads worker `MessageChannel` internal usage for IPC.
 342
 343 ## [2.6.3] - 2023-06-19
 344
 345 ### Fixed
 346
 347 - Ensure no tasks are queued when trying to soft kill a dynamic worker.
 348 - Update strategies internals after statistics computation.
 349
 350 ### Changed
 351
 352 - Optimize O(1) queue implementation.
 353
 354 ## [2.6.2] - 2023-06-12
 355
 356 ### Fixed
 357
 358 - Fix new worker use after creation in dynamic pool given the current worker choice strategy.
 359
 360 ## [2.6.1] - 2023-06-10
 361
 362 ### Added
 363
 364 - Add worker choice strategy documentation: [README.md](./docs/worker-choice-strategies.md).
 365
 366 ### Fixed
 367
 368 - Fix average statistics computation: ensure failed tasks are not accounted.
 369
 370 ## [2.6.0] - 2023-06-09
 371
 372 ### Added
 373
 374 - Add `LEAST_ELU` worker choice strategy (experimental).
 375 - Add tasks ELU instead of runtime support to `FAIR_SHARE` worker choice strategy.
 376
 377 ### Changed
 378
 379 - Refactor pool worker node usage internals.
 380 - Breaking change: refactor worker choice strategy statistics requirements: the syntax of the worker choice strategy options has changed.
 381 - Breaking change: pool information `info` property object fields have been renamed.
 382
 383 ### Fixed
 384
 385 - Fix wait time accounting.
 386 - Ensure worker choice strategy `LEAST_BUSY` accounts also tasks wait time.
 387 - Ensure worker choice strategy `LEAST_USED` accounts also queued tasks.
 388
 389 ## [2.5.4] - 2023-06-07
 390
 391 ### Added
 392
 393 - Add Event Loop Utilization (ELU) statistics to worker tasks usage.
 394
 395 ### Changed
 396
 397 - Compute statistics at the worker level only if needed.
 398 - Add `worker_threads` options to thread pool options.
 399
 400 ### Fixed
 401
 402 - Make the `LEAST_BUSY` strategy only relies on task runtime.
 403
 404 ## [2.5.3] - 2023-06-04
 405
 406 ### Changed
 407
 408 - Refine pool information content.
 409 - Limit pool internals public exposure.
 410
 411 ## [2.5.2] - 2023-06-02
 412
 413 ### Added
 414
 415 - Add `taskError` pool event for task execution error.
 416 - Add pool information `info` property to pool.
 417 - Emit pool information on `busy` and `full` pool events.
 418
 419 ## [2.5.1] - 2023-06-01
 420
 421 ### Added
 422
 423 - Add pool option `restartWorkerOnError` to restart worker on uncaught error. Default to `true`.
 424 - Add `error` pool event for uncaught worker error.
 425
 426 ## [2.5.0] - 2023-05-31
 427
 428 ### Added
 429
 430 - Switch pool event emitter to `EventEmitterAsyncResource`.
 431 - Add tasks wait time accounting in per worker tasks usage.
 432 - Add interleaved weighted round robin `INTERLEAVED_WEIGHTED_ROUND_ROBIN` worker choice strategy (experimental).
 433
 434 ### Changed
 435
 436 - Renamed worker choice strategy `LESS_BUSY` to `LEAST_BUSY` and `LESS_USED` to `LEAST_USED`.
 437
 438 ## [2.4.14] - 2023-05-09
 439
 440 ### Fixed
 441
 442 - Ensure no undefined task runtime can land in the tasks history.
 443 - Fix median computation implementation once again.
 444
 445 ### Added
 446
 447 - Unit tests for median and queue implementations.
 448
 449 ## [2.4.13] - 2023-05-08
 450
 451 ### Fixed
 452
 453 - Fix worker choice strategy options validation.
 454 - Fix fair share worker choice strategy internals update: ensure virtual task end timestamp is computed at task submission.
 455
 456 ## [2.4.12] - 2023-05-06
 457
 458 ### Added
 459
 460 - Support multiple task functions per worker.
 461 - Add custom worker weights support to worker choice strategies options.
 462
 463 ### Changed
 464
 465 - Use O(1) queue implementation for tasks queueing.
 466
 467 ### Fixed
 468
 469 - Fix median computation implementation.
 470 - Fix fair share worker choice strategy internals update.
 471
 472 ## [2.4.11] - 2023-04-23
 473
 474 ### Changed
 475
 476 - Optimize free worker finding in worker choice strategies.
 477
 478 ## [2.4.10] - 2023-04-15
 479
 480 ### Fixed
 481
 482 - Fix typescript type definition for task function: ensure the input data is optional.
 483 - Fix typescript type definition for pool execute(): ensure the input data is optional.
 484
 485 ## [2.4.9] - 2023-04-15
 486
 487 ### Added
 488
 489 - Add tasks queue enablement runtime setter to pool.
 490 - Add tasks queue options runtime setter to pool.
 491 - Add worker choice strategy options runtime setter to pool.
 492
 493 ### Changed
 494
 495 - Remove the tasks queuing experimental status.
 496
 497 ### Fixed
 498
 499 - Fix task function type definition and validation.
 500 - Fix worker choice strategy options handling.
 501
 502 ## [2.4.8] - 2023-04-12
 503
 504 ### Fixed
 505
 506 - Fix message between main worker and worker type definition for tasks.
 507 - Fix code documentation.
 508
 509 ## [2.4.7] - 2023-04-11
 510
 511 ### Added
 512
 513 - Add worker tasks queue options to pool options.
 514
 515 ### Fixed
 516
 517 - Fix missing documentation.
 518
 519 ## [2.4.6] - 2023-04-10
 520
 521 ### Fixed
 522
 523 - Ensure one task at a time is executed per worker with tasks queueing enabled.
 524 - Properly count worker executing tasks with tasks queueing enabled.
 525
 526 ## [2.4.5] - 2023-04-09
 527
 528 ### Added
 529
 530 - Use monotonic high resolution timer for worker tasks runtime.
 531 - Add worker tasks median runtime to statistics.
 532 - Add worker tasks queue (experimental).
 533
 534 ## [2.4.4] - 2023-04-07
 535
 536 ### Added
 537
 538 - Add `PoolEvents` enumeration and `PoolEvent` type.
 539
 540 ### Fixed
 541
 542 - Destroy worker only on alive check.
 543
 544 ## [2.4.3] - 2023-04-07
 545
 546 ### Fixed
 547
 548 - Fix typedoc generation with inheritance.
 549
 550 ## [2.4.2] - 2023-04-06
 551
 552 ### Added
 553
 554 - Add `full` event to dynamic pool.
 555 - Keep worker choice strategy in memory for conditional reuse.
 556
 557 ### Fixed
 558
 559 - Fix possible negative worker key at worker removal in worker choice strategies.
 560
 561 ## [2.4.1] - 2023-04-05
 562
 563 ### Changed
 564
 565 - Optimize worker choice strategy for dynamic pool.
 566
 567 ### Fixed
 568
 569 - Ensure dynamic pool does not alter worker choice strategy expected behavior.
 570
 571 ## [2.4.0] - 2023-04-04
 572
 573 ### Added
 574
 575 - Add `LESS_BUSY` worker choice strategy.
 576
 577 ### Changed
 578
 579 - Optimize worker storage in pool.
 580 - Optimize worker alive status check.
 581 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 582 - Optimize `LESS_USED` worker choice strategy.
 583 - Update benchmarks versus external threads pools.
 584 - Optimize tasks usage statistics requirements for worker choice strategy.
 585
 586 ### Fixed
 587
 588 - Ensure trimmable characters are checked at pool initialization.
 589 - Fix message id integer overflow.
 590 - Fix pool worker removal in worker choice strategy internals.
 591 - Fix package publication with pnpm.
 592
 593 ## [2.4.0-3] - 2023-04-04
 594
 595 ### Added
 596
 597 - Add `LESS_BUSY` worker choice strategy.
 598
 599 ### Changed
 600
 601 - Optimize worker storage in pool.
 602 - Optimize worker alive status check.
 603 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 604 - Optimize `LESS_USED` worker choice strategy.
 605 - Update benchmarks versus external threads pools.
 606
 607 ### Fixed
 608
 609 - Ensure trimmable characters are checked at pool initialization.
 610 - Fix message id integer overflow.
 611 - Fix pool worker removal in worker choice strategy internals.
 612 - Fix package publication with pnpm.
 613
 614 ## [2.4.0-2] - 2023-04-03
 615
 616 ### Added
 617
 618 - Add `LESS_BUSY` worker choice strategy.
 619
 620 ### Changed
 621
 622 - Optimize worker storage in pool.
 623 - Optimize worker alive status check.
 624 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 625 - Optimize `LESS_USED` worker choice strategy.
 626
 627 ### Fixed
 628
 629 - Ensure trimmable characters are checked at pool initialization.
 630 - Fix message id integer overflow.
 631 - Fix pool worker removal in worker choice strategy internals.
 632 - Fix package publication with pnpm.
 633
 634 ## [2.4.0-1] - 2023-04-03
 635
 636 ### Added
 637
 638 - Add `LESS_BUSY` worker choice strategy.
 639
 640 ### Changed
 641
 642 - Optimize worker storage in pool.
 643 - Optimize worker alive status check.
 644 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 645 - Optimize `LESS_USED` worker choice strategy.
 646
 647 ### Fixed
 648
 649 - Ensure trimmable characters are checked at pool initialization.
 650 - Fix message id integer overflow.
 651 - Fix pool worker removal in worker choice strategy internals.
 652
 653 ## [2.4.0-0] - 2023-04-03
 654
 655 ### Added
 656
 657 - Add `LESS_BUSY` worker choice strategy.
 658
 659 ### Changed
 660
 661 - Optimize worker storage in pool.
 662 - Optimize worker alive status check.
 663 - BREAKING CHANGE: Rename worker choice strategy `LESS_RECENTLY_USED` to `LESS_USED`.
 664 - Optimize `LESS_USED` worker choice strategy.
 665
 666 ### Fixed
 667
 668 - Ensure trimmable characters are checked at pool initialization.
 669 - Fix message id integer overflow.
 670 - Fix pool worker removal in worker choice strategy internals.
 671
 672 ## [2.3.10] - 2023-03-18
 673
 674 ### Fixed
 675
 676 - Fix package.json `exports` syntax for ESM and CommonJS.
 677
 678 ### Changed
 679
 680 - Permit SemVer pre-release publication.
 681
 682 ## [2.3.10-2] - 2023-03-18
 683
 684 ### Fixed
 685
 686 - Fix package.json `exports` syntax for ESM and CommonJS.
 687
 688 ## [2.3.10-1] - 2023-03-18
 689
 690 ### Changed
 691
 692 - Permit SemVer pre-release publication.
 693
 694 ## [2.3.10-0] - 2023-03-18
 695
 696 ### Fixed
 697
 698 - Fix package.json `exports` syntax for ESM and CommonJS.
 699
 700 ## [2.3.9] - 2023-03-18
 701
 702 ### Changed
 703
 704 - Introduce ESM module support along with CommonJS one.
 705
 706 ### Fixed
 707
 708 - Fix brown paper bag bug referencing the same object literal.
 709
 710 ## [2.3.8] - 2023-03-18
 711
 712 ### Changed
 713
 714 - Switch internal benchmarking code to benny.
 715 - Switch to TypeScript 5.x.x.
 716 - Switch rollup bundler plugins to core ones.
 717 - Switch to TSDoc syntax.
 718 - Enforce conventional commits.
 719
 720 ### Fixed
 721
 722 - Fix random integer generator.
 723 - Fix worker choice strategy pool type identification at initialization.
 724
 725 ## [2.3.7] - 2022-10-23
 726
 727 ### Changed
 728
 729 - Switch to open collective FOSS project funding platform.
 730 - Switch to ts-standard linter configuration on TypeScript code.
 731
 732 ### Fixed
 733
 734 - Fixed missing async on pool execute method.
 735 - Fixed typing in TypeScript example.
 736 - Fixed types in unit tests.
 737
 738 ## [2.3.6] - 2022-10-22
 739
 740 ### Changed
 741
 742 - Cleanup pool attributes and methods.
 743 - Refine error types thrown.
 744
 745 ### Fixed
 746
 747 - Fix continuous integration build on windows.
 748 - Fix code coverage reporting by using c8 instead of nyc.
 749
 750 ## [2.3.5] - 2022-10-21
 751
 752 ### Changed
 753
 754 - Improve benchmarks: add IO intensive task workload, add task size option, integrate code into linter.
 755 - Optimize tasks usage lookup implementation.
 756
 757 ### Fixed
 758
 759 - Fix missed pool event emitter type export.
 760 - Fix typedoc documentation generation.
 761
 762 ## [2.3.4] - 2022-10-17
 763
 764 ### Added
 765
 766 - Fully automate release process with release-it.
 767
 768 ### Changed
 769
 770 - Optimize fair share task scheduling algorithm implementation.
 771 - Update benchmarks versus external pools results with latest version.
 772
 773 ## [2.3.3] - 2022-10-15
 774
 775 ### Added
 776
 777 - Add support for [cluster settings](https://nodejs.org/api/cluster.html#cluster_cluster_settings) in cluster pool options.
 778
 779 ## [2.3.2] - 2022-10-14
 780
 781 ### Changed
 782
 783 - Optimize fair share worker selection strategy implementation.
 784
 785 ### Fixed
 786
 787 - Fix WRR worker selection strategy: ensure the condition triggering the round robin can be fulfilled.
 788
 789 ## [2.3.1] - 2022-10-13
 790
 791 ### Added
 792
 793 - Pool worker choice strategies:
 794   - `WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN` strategy based on weighted round robin scheduling algorithm using tasks execution time for now.
 795   - `WorkerChoiceStrategies.FAIR_SHARE` strategy based on fair share scheduling algorithm using tasks execution time for now.
 796
 797 ## [2.2.2] - 2022-10-09
 798
 799 ### Fixed
 800
 801 - Fixed `README.md` file.
 802
 803 ## [2.2.1] - 2022-10-08
 804
 805 ### Added
 806
 807 - Dynamic worker choice strategy change at runtime.
 808
 809 ## [2.2.0] - 2022-01-05
 810
 811 ### Breaking Changes
 812
 813 - Support only Node.js version 16.x.x for cluster pool: upstream cluster API have changed on that version.
 814
 815 ## [2.1.0] - 2021-08-29
 816
 817 ### Added
 818
 819 - Add an optional pool option `messageHandler` to `PoolOptions<Worker>` for registering a message handler callback on each worker.
 820
 821 ### Breaking Changes
 822
 823 - `AbstractWorker` class `maxInactiveTime`, `killBehavior` and `async` attributes have been removed in favour of the same ones in the worker options `opts` public attribute.
 824 - `AbstractWorker` class `lastTask` attribute have been renamed to `lastTaskTimestamp`.
 825 - `AbstractWorker` class `interval` attribute have been renamed to `aliveInterval`.
 826 - `AbstractWorker` class cannot be instantiated without specifying the `mainWorker` argument referencing the main worker.
 827
 828 ## [2.0.2] - 2021-05-12
 829
 830 ### Bug fixes
 831
 832 - Fix `busy` event emission on fixed pool type
 833
 834 ## [2.0.1] - 2021-03-16
 835
 836 ### Bug fixes
 837
 838 - Check if pool options are properly set.
 839 - `busy` event is emitted on all pool types.
 840
 841 ## [2.0.0] - 2021-03-01
 842
 843 ### Bug fixes
 844
 845 - Now a thread/process by default is not deleted when the task submitted take more time than maxInactiveTime configured (issue #70).
 846
 847 ### Breaking Changes
 848
 849 - `FullPool` event is now renamed to `busy`.
 850 - `maxInactiveTime` on `ThreadWorker` default behavior is now changed, if you want to keep the old behavior set `killBehavior` to `KillBehaviors.HARD`.
 851   _Find more details on our JSDoc._
 852
 853 - `maxTasks` option on `FixedThreadPool` and `DynamicThreadPool` is now removed since is no more needed.
 854
 855 - We changed some internal structures, but you shouldn't be too affected by them as these are internal changes.
 856
 857 ### Pool options types declaration merge
 858
 859 `FixedThreadPoolOptions` and `DynamicThreadPoolOptions` type declarations have been merged to `PoolOptions<Worker>`.
 860
 861 #### New `export` strategy
 862
 863 ```js
 864 // Before
 865 const DynamicThreadPool = require('poolifier/lib/dynamic')
 866 // After
 867 const { DynamicThreadPool } = require('poolifier/lib/dynamic')
 868 ```
 869
 870 But you should always prefer just using
 871
 872 ```js
 873 const { DynamicThreadPool } = require('poolifier')
 874 ```
 875
 876 #### New type definitions for input data and response
 877
 878 For cluster worker and worker-thread pools, you can now only send and receive structured-cloneable data.
 879 _This is not a limitation by poolifier but Node.js._
 880
 881 #### Public property replacements
 882
 883 `numWorkers` property is now `numberOfWorkers`
 884
 885 #### Internal (protected) properties and methods renaming
 886
 887 These properties are not intended for end users
 888
 889 - `id` => `nextMessageId`
 890
 891 These methods are not intended for end users
 892
 893 - `_chooseWorker` => `chooseWorker`
 894 - `_newWorker` => `createWorker`
 895 - `_execute` => `internalExecute`
 896 - `_chooseWorker` => `chooseWorker`
 897 - `_checkAlive` => `checkAlive`
 898 - `_run` => `run`
 899 - `_runAsync` => `runAsync`
 900
 901 ## [1.1.0] - 2020-05-21
 902
 903 ### Added
 904
 905 - ThreadWorker support async functions as option
 906 - Various external library patches
 907
 908 ## [1.0.0] - 2020-01-24
 909
 910 ### Added
 911
 912 - FixedThreadPool implementation
 913 - DynamicThreadPool implementation
 914 - WorkerThread implementation to improve developer experience