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