All files / lib events.js

99.12% Statements 1127/1137
97.88% Branches 278/284
100% Functions 58/58
99.12% Lines 1127/1137

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 113831x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 1004x 1004x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 3x 3x 3x 251x 251x 251x 251x 251x 1x 1x 1x 1x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 251x 3x 3x 1x 1x 3x 2x     2x 2x 3x 3x 3x 3x 3x 251x 251x 251x 251x 251x 251x 251x 2x 2x 1x 1x 1x 1x 2x 251x 251x 251x 251x 251x 2x 2x 1x 2x 251x 251x 251x 251x 251x 2x 2x 1x 2x 251x 251x 251x 251x 251x 2x 2x 1x 2x 251x 251x 251x 251x 251x 9x 9x 8x 9x 251x 251x 1004x 1004x 31x 31x 31x 31x 31x 31x 244217x 244217x 244217x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 1005x 31x 31x 12x 12x 12x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 844665x 844665x 844665x 31x 31x 31x 31x 119015x 31x 31x 10x 3x 3x 3x 3x 10x 10x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 9x 9x 9x 1x 9x 5x 5x 5x 5x 5x 5x 3x 3x 5x 1x 1x 1x 1x 1x 1x 1x 5x 4x 31x 31x 31x 31x 31x 244217x 244217x 244217x 147135x 147135x 147135x 244217x 244217x 244217x 244217x 244217x 14x 14x 244215x 244203x 244203x 244203x 244203x 31x 31x 11354x 11354x 11323x 11323x 11354x 11354x 11354x 11354x 11354x 11354x 11354x 27x 26x 26x 26x 27x 27x 11354x 1x 1x 11354x 31x 26x 26x 17x 26x 9x 9x 9x 9x 9x 9x 9x 9x 9x 9x 9x 9x 9x 9x 9x 26x 31x 31x 31x 31x 31x 31x 31x 3238x 3x 3x 3235x 3235x 31x 31x 89529x 89529x 89529x 7406x 89529x 31x 31x 31x 31x 31x 31x 22x 31x 31x 31x 31x 6x 6x 7x 7x 7x 3x 3x 3x 3x 3x 3x 15x 15x 3x 3x 3x 3x 3x 7x 3x 3x 6x 31x 6x 6x 6x 6x 6x 6x 6x     6x 6x 6x 6x 6x 6x 6x 6x 6x 3x 3x 3x 6x 6x 6x 31x 31x 31x 31x 31x 31x 31x 31x 31x 1143314x 1143314x 1143314x 1143314x 1143311x 1143311x 1143311x 1143314x 3x 1143314x 1143314x 1143314x 29x 29x 29x 29x 26x 26x 26x 26x 26x 26x 26x 26x     26x 26x 26x 26x 26x 3x 3x 3x 3x 3x 1x 1x 3x 3x 3x 3x 3x 3x 1143284x 1143284x 1143284x 1143284x 1143314x 695561x 1143018x 616423x 616423x 616423x 616423x 616423x 616423x 9465x 9465x 1143314x 79138x 79138x 79138x 237978x 237978x 237978x 237978x 237978x 237978x 237978x 237978x 1881x 1881x 237978x 78936x 1142318x 1142318x 31x 31x 573579x 573579x 573579x 573579x 573579x 573579x 573579x 573579x 573579x 12458x 12458x 573579x 561120x 561120x 561120x 182638x 182638x 182638x 182638x 182638x 182638x 182638x 561120x 561120x 573578x 573578x 484067x 484067x 484067x 573579x 89507x 77675x 77675x 77675x 77675x 89507x 1273x 11828x 10559x 10559x 89507x 89507x 89507x 89507x 12x 12x 12x 12x 12x 12x 12x 12x 89507x 573579x 573579x 573579x 31x 31x 31x 31x 31x 31x 31x 31x 568943x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 4636x 31x 31x 61080x 61080x 61079x 61079x 61079x 61079x 50364x 50364x 61080x 31x 107714x 107714x 107714x 107714x 107714x 107714x 107714x 31x 31x 31x 31x 31x 31x 31x 31x 107714x 107714x 107714x 107714x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 2x 2x 2x 2x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 163370x 163370x 163370x 163370x 163370x 163369x 163369x 163369x 163369x 163324x 163370x 78986x 78986x 62891x 62891x 62891x 62891x 62891x 162571x 74713x 74713x 74713x 1282779x 46324x 46324x 46324x 1282779x 74713x 74713x 74713x 46324x 46324x 74700x 74713x 74713x 74713x 74713x 74713x 74713x 74713x 74713x 46324x 46324x 74713x 74713x 162571x 162571x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 41544x 41544x 41544x 41544x 41544x 41544x 12607x 5x 5x 12606x 64x 64x 64x 64x 64x 12607x 12607x 28936x 28936x 28941x 782x 2283x 1501x 1501x 782x 782x 782x 782x 782x 28941x 28941x 28941x 28941x 2931x 28707x 164x 164x 329x 329x 164x 28941x 28941x 31x 31x 149x 149x 149x 149x 149x 149x 149x 149x 149x 134x 134x 146x 149x 149x 149x 149x 31x 31x 31x 31x 31x 31x 31x 31x 137x 31x 31x 31x 31x 31x 31x 31x 31x 31x 12x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 1101x 1100x 1100x 1x 31x 31x 31x 31x 31x 31x 31x 31x 31x 31x 320133x 320133x 320133x 320133x 320131x 320131x 320131x 176554x 319245x 61345x 61345x 320131x 82234x 82234x 320133x 31x 31x 31x 31x 31x 31x 31x 8x 31x 31x 79536x 79536x 79536x 79536x 79536x 79536x 79536x 79536x 79536x 79536x 944x 79536x 31x 24x 24x 24x 52x 52x 52x 52x 24x 24x 31x 31x 31x 31x 31x 31x 31x 31x 54x 54x 54x 3x 3x 51x 51x 54x 50x 50x 50x 50x 31x 31x 31x 31x 31x 50x 50x 54x 54x 54x 54x 31x 31x 31x 31x 31x 31x 31x 31x 31x 20200x 20200x 20200x 20200x 20200x 20188x 20188x 15x 15x     15x 20188x 20188x 20170x 20158x 20158x 20170x 2x 2x 20170x 20188x 20188x 20188x 20152x 20152x 20188x 5x 5x 5x 5x 20188x 5x 5x 5x 20188x 20200x 31x 31x 31x 31x 48x 48x 48x 31x 47x 47x 30x 41x 17x 17x     47x 31x 20213x 20213x 20187x 20175x 20187x 12x 12x 20213x 25x 25x 25x 26x 1x 1x 20213x 31x 31x 31x 31x 31x 31x 31x 31x 28x 28x 28x 28x 28x 16x 16x 16x 16x 16x 16x 16x 16x 41x 41x 41x 2x 2x 41x 41x 41x 41x 41x 3x 3x 3x 3x 3x 36x 36x 41x 1x 1x 41x 41x 41x 35x 41x 16x 16x 16x 14x 14x 14x 14x 5x 5x 5x 5x 5x 5x 14x 14x 14x 14x 3x 3x 14x 14x 16x 16x 16x 2x 1x 1x 1x 1x 1x 1x 16x 16x 16x 12x 12x 16x 16x 16x 28x 12x 12x 28x 28x 4x 4x 4x 4x 4x 4x 15x 15x 15x 15x 4x 4x 15x 15x 30x 30x 28x 30x 2x 2x 30x 15x 15x 7x 7x 7x 7x 7x 4x 7x 3x 3x 3x 7x 7x 7x 28x  
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
 
'use strict';
 
const {
  ArrayPrototypeIndexOf,
  ArrayPrototypeJoin,
  ArrayPrototypeShift,
  ArrayPrototypeSlice,
  ArrayPrototypeSplice,
  ArrayPrototypeUnshift,
  Boolean,
  Error,
  ErrorCaptureStackTrace,
  FunctionPrototypeBind,
  FunctionPrototypeCall,
  MathMin,
  NumberIsNaN,
  ObjectCreate,
  ObjectDefineProperty,
  ObjectDefineProperties,
  ObjectGetPrototypeOf,
  ObjectSetPrototypeOf,
  Promise,
  PromiseReject,
  PromiseResolve,
  ReflectApply,
  ReflectOwnKeys,
  String,
  StringPrototypeSplit,
  Symbol,
  SymbolFor,
  SymbolAsyncIterator,
} = primordials;
const kRejection = SymbolFor('nodejs.rejection');
const { inspect } = require('internal/util/inspect');
 
let spliceOne;
 
const {
  AbortError,
  kEnhanceStackBeforeInspector,
  codes: {
    ERR_INVALID_ARG_TYPE,
    ERR_INVALID_THIS,
    ERR_OUT_OF_RANGE,
    ERR_UNHANDLED_ERROR
  },
  genericNodeError,
} = require('internal/errors');
 
const {
  validateAbortSignal,
  validateBoolean,
  validateFunction,
  validateString,
} = require('internal/validators');
 
const kCapture = Symbol('kCapture');
const kErrorMonitor = Symbol('events.errorMonitor');
const kMaxEventTargetListeners = Symbol('events.maxEventTargetListeners');
const kMaxEventTargetListenersWarned =
  Symbol('events.maxEventTargetListenersWarned');
 
let EventEmitterAsyncResource;
// The EventEmitterAsyncResource has to be initialized lazily because event.js
// is loaded so early in the bootstrap process, before async_hooks is available.
//
// This implementation was adapted straight from addaleax's
// eventemitter-asyncresource MIT-licensed userland module.
// https://github.com/addaleax/eventemitter-asyncresource
function lazyEventEmitterAsyncResource() {
  if (EventEmitterAsyncResource === undefined) {
    const {
      AsyncResource
    } = require('async_hooks');
 
    const kEventEmitter = Symbol('kEventEmitter');
    const kAsyncResource = Symbol('kAsyncResource');
    class EventEmitterReferencingAsyncResource extends AsyncResource {
      /**
       * @param {EventEmitter} ee
       * @param {string} [type]
       * @param {{
       *   triggerAsyncId?: number,
       *   requireManualDestroy?: boolean,
       * }} [options]
       */
      constructor(ee, type, options) {
        super(type, options);
        this[kEventEmitter] = ee;
      }
 
      /**
       * @type {EventEmitter}
       */
      get eventEmitter() {
        if (this[kEventEmitter] === undefined)
          throw new ERR_INVALID_THIS('EventEmitterReferencingAsyncResource');
        return this[kEventEmitter];
      }
    }
 
    EventEmitterAsyncResource =
      class EventEmitterAsyncResource extends EventEmitter {
        /**
         * @param {{
         *   name?: string,
         *   triggerAsyncId?: number,
         *   requireManualDestroy?: boolean,
         * }} [options]
         */
        constructor(options = undefined) {
          let name;
          if (typeof options === 'string') {
            name = options;
            options = undefined;
          } else {
            if (new.target === EventEmitterAsyncResource) {
              validateString(options?.name, 'options.name');
            }
            name = options?.name || new.target.name;
          }
          super(options);
 
          this[kAsyncResource] =
            new EventEmitterReferencingAsyncResource(this, name, options);
        }
 
        /**
         * @param {symbol,string} event
         * @param  {...any} args
         * @returns {boolean}
         */
        emit(event, ...args) {
          if (this[kAsyncResource] === undefined)
            throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
          const { asyncResource } = this;
          ArrayPrototypeUnshift(args, super.emit, this, event);
          return ReflectApply(asyncResource.runInAsyncScope, asyncResource,
                              args);
        }
 
        /**
         * @returns {void}
         */
        emitDestroy() {
          if (this[kAsyncResource] === undefined)
            throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
          this.asyncResource.emitDestroy();
        }
 
        /**
         * @type {number}
         */
        get asyncId() {
          if (this[kAsyncResource] === undefined)
            throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
          return this.asyncResource.asyncId();
        }
 
        /**
         * @type {number}
         */
        get triggerAsyncId() {
          if (this[kAsyncResource] === undefined)
            throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
          return this.asyncResource.triggerAsyncId();
        }
 
        /**
         * @type {EventEmitterReferencingAsyncResource}
         */
        get asyncResource() {
          if (this[kAsyncResource] === undefined)
            throw new ERR_INVALID_THIS('EventEmitterAsyncResource');
          return this[kAsyncResource];
        }
      };
  }
  return EventEmitterAsyncResource;
}
 
/**
 * Creates a new `EventEmitter` instance.
 * @param {{ captureRejections?: boolean; }} [opts]
 * @constructs {EventEmitter}
 */
function EventEmitter(opts) {
  EventEmitter.init.call(this, opts);
}
module.exports = EventEmitter;
module.exports.once = once;
module.exports.on = on;
module.exports.getEventListeners = getEventListeners;
// Backwards-compat with node 0.10.x
EventEmitter.EventEmitter = EventEmitter;
 
EventEmitter.usingDomains = false;
 
EventEmitter.captureRejectionSymbol = kRejection;
ObjectDefineProperty(EventEmitter, 'captureRejections', {
  get() {
    return EventEmitter.prototype[kCapture];
  },
  set(value) {
    validateBoolean(value, 'EventEmitter.captureRejections');
 
    EventEmitter.prototype[kCapture] = value;
  },
  enumerable: true
});
 
ObjectDefineProperty(EventEmitter, 'EventEmitterAsyncResource', {
  enumerable: true,
  get: lazyEventEmitterAsyncResource,
  set: undefined,
  configurable: true,
});
 
EventEmitter.errorMonitor = kErrorMonitor;
 
// The default for captureRejections is false
ObjectDefineProperty(EventEmitter.prototype, kCapture, {
  value: false,
  writable: true,
  enumerable: false
});
 
EventEmitter.prototype._events = undefined;
EventEmitter.prototype._eventsCount = 0;
EventEmitter.prototype._maxListeners = undefined;
 
// By default EventEmitters will print a warning if more than 10 listeners are
// added to it. This is a useful default which helps finding memory leaks.
let defaultMaxListeners = 10;
let isEventTarget;
 
function checkListener(listener) {
  validateFunction(listener, 'listener');
}
 
ObjectDefineProperty(EventEmitter, 'defaultMaxListeners', {
  enumerable: true,
  get: function() {
    return defaultMaxListeners;
  },
  set: function(arg) {
    if (typeof arg !== 'number' || arg < 0 || NumberIsNaN(arg)) {
      throw new ERR_OUT_OF_RANGE('defaultMaxListeners',
                                 'a non-negative number',
                                 arg);
    }
    defaultMaxListeners = arg;
  }
});
 
ObjectDefineProperties(EventEmitter, {
  kMaxEventTargetListeners: {
    value: kMaxEventTargetListeners,
    enumerable: false,
    configurable: false,
    writable: false,
  },
  kMaxEventTargetListenersWarned: {
    value: kMaxEventTargetListenersWarned,
    enumerable: false,
    configurable: false,
    writable: false,
  }
});
 
/**
 * Sets the max listeners.
 * @param {number} n
 * @param {EventTarget[] | EventEmitter[]} [eventTargets]
 * @returns {void}
 */
EventEmitter.setMaxListeners =
  function(n = defaultMaxListeners, ...eventTargets) {
    if (typeof n !== 'number' || n < 0 || NumberIsNaN(n))
      throw new ERR_OUT_OF_RANGE('n', 'a non-negative number', n);
    if (eventTargets.length === 0) {
      defaultMaxListeners = n;
    } else {
      if (isEventTarget === undefined)
        isEventTarget = require('internal/event_target').isEventTarget;
 
      for (let i = 0; i < eventTargets.length; i++) {
        const target = eventTargets[i];
        if (isEventTarget(target)) {
          target[kMaxEventTargetListeners] = n;
          target[kMaxEventTargetListenersWarned] = false;
        } else if (typeof target.setMaxListeners === 'function') {
          target.setMaxListeners(n);
        } else {
          throw new ERR_INVALID_ARG_TYPE(
            'eventTargets',
            ['EventEmitter', 'EventTarget'],
            target);
        }
      }
    }
  };
 
// If you're updating this function definition, please also update any
// re-definitions, such as the one in the Domain module (lib/domain.js).
EventEmitter.init = function(opts) {
 
  if (this._events === undefined ||
      this._events === ObjectGetPrototypeOf(this)._events) {
    this._events = ObjectCreate(null);
    this._eventsCount = 0;
  }
 
  this._maxListeners = this._maxListeners || undefined;
 
 
  if (opts?.captureRejections) {
    validateBoolean(opts.captureRejections, 'options.captureRejections');
    this[kCapture] = Boolean(opts.captureRejections);
  } else {
    // Assigning the kCapture property directly saves an expensive
    // prototype lookup in a very sensitive hot path.
    this[kCapture] = EventEmitter.prototype[kCapture];
  }
};
 
function addCatch(that, promise, type, args) {
  if (!that[kCapture]) {
    return;
  }
 
  // Handle Promises/A+ spec, then could be a getter
  // that throws on second use.
  try {
    const then = promise.then;
 
    if (typeof then === 'function') {
      then.call(promise, undefined, function(err) {
        // The callback is called with nextTick to avoid a follow-up
        // rejection from this promise.
        process.nextTick(emitUnhandledRejectionOrErr, that, err, type, args);
      });
    }
  } catch (err) {
    that.emit('error', err);
  }
}
 
function emitUnhandledRejectionOrErr(ee, err, type, args) {
  if (typeof ee[kRejection] === 'function') {
    ee[kRejection](err, type, ...args);
  } else {
    // We have to disable the capture rejections mechanism, otherwise
    // we might end up in an infinite loop.
    const prev = ee[kCapture];
 
    // If the error handler throws, it is not catchable and it
    // will end up in 'uncaughtException'. We restore the previous
    // value of kCapture in case the uncaughtException is present
    // and the exception is handled.
    try {
      ee[kCapture] = false;
      ee.emit('error', err);
    } finally {
      ee[kCapture] = prev;
    }
  }
}
 
/**
 * Increases the max listeners of the event emitter.
 * @param {number} n
 * @returns {EventEmitter}
 */
EventEmitter.prototype.setMaxListeners = function setMaxListeners(n) {
  if (typeof n !== 'number' || n < 0 || NumberIsNaN(n)) {
    throw new ERR_OUT_OF_RANGE('n', 'a non-negative number', n);
  }
  this._maxListeners = n;
  return this;
};
 
function _getMaxListeners(that) {
  if (that._maxListeners === undefined)
    return EventEmitter.defaultMaxListeners;
  return that._maxListeners;
}
 
/**
 * Returns the current max listener value for the event emitter.
 * @returns {number}
 */
EventEmitter.prototype.getMaxListeners = function getMaxListeners() {
  return _getMaxListeners(this);
};
 
// Returns the length and line number of the first sequence of `a` that fully
// appears in `b` with a length of at least 4.
function identicalSequenceRange(a, b) {
  for (let i = 0; i < a.length - 3; i++) {
    // Find the first entry of b that matches the current entry of a.
    const pos = ArrayPrototypeIndexOf(b, a[i]);
    if (pos !== -1) {
      const rest = b.length - pos;
      if (rest > 3) {
        let len = 1;
        const maxLen = MathMin(a.length - i, rest);
        // Count the number of consecutive entries.
        while (maxLen > len && a[i + len] === b[pos + len]) {
          len++;
        }
        if (len > 3) {
          return [len, i];
        }
      }
    }
  }
 
  return [0, 0];
}
 
function enhanceStackTrace(err, own) {
  let ctorInfo = '';
  try {
    const { name } = this.constructor;
    if (name !== 'EventEmitter')
      ctorInfo = ` on ${name} instance`;
  } catch {
    // Continue regardless of error.
  }
  const sep = `\nEmitted 'error' event${ctorInfo} at:\n`;
 
  const errStack = ArrayPrototypeSlice(
    StringPrototypeSplit(err.stack, '\n'), 1);
  const ownStack = ArrayPrototypeSlice(
    StringPrototypeSplit(own.stack, '\n'), 1);
 
  const { 0: len, 1: off } = identicalSequenceRange(ownStack, errStack);
  if (len > 0) {
    ArrayPrototypeSplice(ownStack, off + 1, len - 2,
                         '    [... lines matching original stack trace ...]');
  }
 
  return err.stack + sep + ArrayPrototypeJoin(ownStack, '\n');
}
 
/**
 * Synchronously calls each of the listeners registered
 * for the event.
 * @param {string | symbol} type
 * @param {...any} [args]
 * @returns {boolean}
 */
EventEmitter.prototype.emit = function emit(type, ...args) {
  let doError = (type === 'error');
 
  const events = this._events;
  if (events !== undefined) {
    if (doError && events[kErrorMonitor] !== undefined)
      this.emit(kErrorMonitor, ...args);
    doError = (doError && events.error === undefined);
  } else if (!doError)
    return false;
 
  // If there is no 'error' event listener then throw.
  if (doError) {
    let er;
    if (args.length > 0)
      er = args[0];
    if (er instanceof Error) {
      try {
        const capture = {};
        ErrorCaptureStackTrace(capture, EventEmitter.prototype.emit);
        ObjectDefineProperty(er, kEnhanceStackBeforeInspector, {
          value: FunctionPrototypeBind(enhanceStackTrace, this, er, capture),
          configurable: true
        });
      } catch {
        // Continue regardless of error.
      }
 
      // Note: The comments on the `throw` lines are intentional, they show
      // up in Node's output if this results in an unhandled exception.
      throw er; // Unhandled 'error' event
    }
 
    let stringifiedEr;
    try {
      stringifiedEr = inspect(er);
    } catch {
      stringifiedEr = er;
    }
 
    // At least give some kind of context to the user
    const err = new ERR_UNHANDLED_ERROR(stringifiedEr);
    err.context = er;
    throw err; // Unhandled 'error' event
  }
 
  const handler = events[type];
 
  if (handler === undefined)
    return false;
 
  if (typeof handler === 'function') {
    const result = handler.apply(this, args);
 
    // We check if result is undefined first because that
    // is the most common case so we do not pay any perf
    // penalty
    if (result !== undefined && result !== null) {
      addCatch(this, result, type, args);
    }
  } else {
    const len = handler.length;
    const listeners = arrayClone(handler);
    for (let i = 0; i < len; ++i) {
      const result = listeners[i].apply(this, args);
 
      // We check if result is undefined first because that
      // is the most common case so we do not pay any perf
      // penalty.
      // This code is duplicated because extracting it away
      // would make it non-inlineable.
      if (result !== undefined && result !== null) {
        addCatch(this, result, type, args);
      }
    }
  }
 
  return true;
};
 
function _addListener(target, type, listener, prepend) {
  let m;
  let events;
  let existing;
 
  checkListener(listener);
 
  events = target._events;
  if (events === undefined) {
    events = target._events = ObjectCreate(null);
    target._eventsCount = 0;
  } else {
    // To avoid recursion in the case that type === "newListener"! Before
    // adding it to the listeners, first emit "newListener".
    if (events.newListener !== undefined) {
      target.emit('newListener', type,
                  listener.listener ?? listener);
 
      // Re-assign `events` because a newListener handler could have caused the
      // this._events to be assigned to a new object
      events = target._events;
    }
    existing = events[type];
  }
 
  if (existing === undefined) {
    // Optimize the case of one listener. Don't need the extra array object.
    events[type] = listener;
    ++target._eventsCount;
  } else {
    if (typeof existing === 'function') {
      // Adding the second element, need to change to array.
      existing = events[type] =
        prepend ? [listener, existing] : [existing, listener];
      // If we've already got an array, just append.
    } else if (prepend) {
      existing.unshift(listener);
    } else {
      existing.push(listener);
    }
 
    // Check for listener leak
    m = _getMaxListeners(target);
    if (m > 0 && existing.length > m && !existing.warned) {
      existing.warned = true;
      // No error code for this since it is a Warning
      const w = genericNodeError(
        `Possible EventEmitter memory leak detected. ${existing.length} ${String(type)} listeners ` +
        `added to ${inspect(target, { depth: -1 })}. Use emitter.setMaxListeners() to increase limit`,
        { name: 'MaxListenersExceededWarning', emitter: target, type: type, count: existing.length });
      process.emitWarning(w);
    }
  }
 
  return target;
}
 
/**
 * Adds a listener to the event emitter.
 * @param {string | symbol} type
 * @param {Function} listener
 * @returns {EventEmitter}
 */
EventEmitter.prototype.addListener = function addListener(type, listener) {
  return _addListener(this, type, listener, false);
};
 
EventEmitter.prototype.on = EventEmitter.prototype.addListener;
 
/**
 * Adds the `listener` function to the beginning of
 * the listeners array.
 * @param {string | symbol} type
 * @param {Function} listener
 * @returns {EventEmitter}
 */
EventEmitter.prototype.prependListener =
    function prependListener(type, listener) {
      return _addListener(this, type, listener, true);
    };
 
function onceWrapper() {
  if (!this.fired) {
    this.target.removeListener(this.type, this.wrapFn);
    this.fired = true;
    if (arguments.length === 0)
      return this.listener.call(this.target);
    return this.listener.apply(this.target, arguments);
  }
}
 
function _onceWrap(target, type, listener) {
  const state = { fired: false, wrapFn: undefined, target, type, listener };
  const wrapped = onceWrapper.bind(state);
  wrapped.listener = listener;
  state.wrapFn = wrapped;
  return wrapped;
}
 
/**
 * Adds a one-time `listener` function to the event emitter.
 * @param {string | symbol} type
 * @param {Function} listener
 * @returns {EventEmitter}
 */
EventEmitter.prototype.once = function once(type, listener) {
  checkListener(listener);
 
  this.on(type, _onceWrap(this, type, listener));
  return this;
};
 
/**
 * Adds a one-time `listener` function to the beginning of
 * the listeners array.
 * @param {string | symbol} type
 * @param {Function} listener
 * @returns {EventEmitter}
 */
EventEmitter.prototype.prependOnceListener =
    function prependOnceListener(type, listener) {
      checkListener(listener);
 
      this.prependListener(type, _onceWrap(this, type, listener));
      return this;
    };
 
/**
 * Removes the specified `listener` from the listeners array.
 * @param {string | symbol} type
 * @param {Function} listener
 * @returns {EventEmitter}
 */
EventEmitter.prototype.removeListener =
    function removeListener(type, listener) {
      checkListener(listener);
 
      const events = this._events;
      if (events === undefined)
        return this;
 
      const list = events[type];
      if (list === undefined)
        return this;
 
      if (list === listener || list.listener === listener) {
        if (--this._eventsCount === 0)
          this._events = ObjectCreate(null);
        else {
          delete events[type];
          if (events.removeListener)
            this.emit('removeListener', type, list.listener || listener);
        }
      } else if (typeof list !== 'function') {
        let position = -1;
 
        for (let i = list.length - 1; i >= 0; i--) {
          if (list[i] === listener || list[i].listener === listener) {
            position = i;
            break;
          }
        }
 
        if (position < 0)
          return this;
 
        if (position === 0)
          list.shift();
        else {
          if (spliceOne === undefined)
            spliceOne = require('internal/util').spliceOne;
          spliceOne(list, position);
        }
 
        if (list.length === 1)
          events[type] = list[0];
 
        if (events.removeListener !== undefined)
          this.emit('removeListener', type, listener);
      }
 
      return this;
    };
 
EventEmitter.prototype.off = EventEmitter.prototype.removeListener;
 
/**
 * Removes all listeners from the event emitter. (Only
 * removes listeners for a specific event name if specified
 * as `type`).
 * @param {string | symbol} [type]
 * @returns {EventEmitter}
 */
EventEmitter.prototype.removeAllListeners =
    function removeAllListeners(type) {
      const events = this._events;
      if (events === undefined)
        return this;
 
      // Not listening for removeListener, no need to emit
      if (events.removeListener === undefined) {
        if (arguments.length === 0) {
          this._events = ObjectCreate(null);
          this._eventsCount = 0;
        } else if (events[type] !== undefined) {
          if (--this._eventsCount === 0)
            this._events = ObjectCreate(null);
          else
            delete events[type];
        }
        return this;
      }
 
      // Emit removeListener for all listeners on all events
      if (arguments.length === 0) {
        for (const key of ReflectOwnKeys(events)) {
          if (key === 'removeListener') continue;
          this.removeAllListeners(key);
        }
        this.removeAllListeners('removeListener');
        this._events = ObjectCreate(null);
        this._eventsCount = 0;
        return this;
      }
 
      const listeners = events[type];
 
      if (typeof listeners === 'function') {
        this.removeListener(type, listeners);
      } else if (listeners !== undefined) {
        // LIFO order
        for (let i = listeners.length - 1; i >= 0; i--) {
          this.removeListener(type, listeners[i]);
        }
      }
 
      return this;
    };
 
function _listeners(target, type, unwrap) {
  const events = target._events;
 
  if (events === undefined)
    return [];
 
  const evlistener = events[type];
  if (evlistener === undefined)
    return [];
 
  if (typeof evlistener === 'function')
    return unwrap ? [evlistener.listener || evlistener] : [evlistener];
 
  return unwrap ?
    unwrapListeners(evlistener) : arrayClone(evlistener);
}
 
/**
 * Returns a copy of the array of listeners for the event name
 * specified as `type`.
 * @param {string | symbol} type
 * @returns {Function[]}
 */
EventEmitter.prototype.listeners = function listeners(type) {
  return _listeners(this, type, true);
};
 
/**
 * Returns a copy of the array of listeners and wrappers for
 * the event name specified as `type`.
 * @param {string | symbol} type
 * @returns {Function[]}
 */
EventEmitter.prototype.rawListeners = function rawListeners(type) {
  return _listeners(this, type, false);
};
 
/**
 * Returns the number of listeners listening to the event name
 * specified as `type`.
 * @deprecated since v3.2.0
 * @param {EventEmitter} emitter
 * @param {string | symbol} type
 * @returns {number}
 */
EventEmitter.listenerCount = function(emitter, type) {
  if (typeof emitter.listenerCount === 'function') {
    return emitter.listenerCount(type);
  }
  return FunctionPrototypeCall(listenerCount, emitter, type);
};
 
EventEmitter.prototype.listenerCount = listenerCount;
 
/**
 * Returns the number of listeners listening to event name
 * specified as `type`.
 * @param {string | symbol} type
 * @returns {number}
 */
function listenerCount(type) {
  const events = this._events;
 
  if (events !== undefined) {
    const evlistener = events[type];
 
    if (typeof evlistener === 'function') {
      return 1;
    } else if (evlistener !== undefined) {
      return evlistener.length;
    }
  }
 
  return 0;
}
 
/**
 * Returns an array listing the events for which
 * the emitter has registered listeners.
 * @returns {any[]}
 */
EventEmitter.prototype.eventNames = function eventNames() {
  return this._eventsCount > 0 ? ReflectOwnKeys(this._events) : [];
};
 
function arrayClone(arr) {
  // At least since V8 8.3, this implementation is faster than the previous
  // which always used a simple for-loop
  switch (arr.length) {
    case 2: return [arr[0], arr[1]];
    case 3: return [arr[0], arr[1], arr[2]];
    case 4: return [arr[0], arr[1], arr[2], arr[3]];
    case 5: return [arr[0], arr[1], arr[2], arr[3], arr[4]];
    case 6: return [arr[0], arr[1], arr[2], arr[3], arr[4], arr[5]];
  }
  return ArrayPrototypeSlice(arr);
}
 
function unwrapListeners(arr) {
  const ret = arrayClone(arr);
  for (let i = 0; i < ret.length; ++i) {
    const orig = ret[i].listener;
    if (typeof orig === 'function')
      ret[i] = orig;
  }
  return ret;
}
 
/**
 * Returns a copy of the array of listeners for the event name
 * specified as `type`.
 * @param {EventEmitter | EventTarget} emitterOrTarget
 * @param {string | symbol} type
 * @returns {Function[]}
 */
function getEventListeners(emitterOrTarget, type) {
  // First check if EventEmitter
  if (typeof emitterOrTarget.listeners === 'function') {
    return emitterOrTarget.listeners(type);
  }
  // Require event target lazily to avoid always loading it
  const { isEventTarget, kEvents } = require('internal/event_target');
  if (isEventTarget(emitterOrTarget)) {
    const root = emitterOrTarget[kEvents].get(type);
    const listeners = [];
    let handler = root?.next;
    while (handler?.listener !== undefined) {
      const listener = handler.listener?.deref ?
        handler.listener.deref() : handler.listener;
      listeners.push(listener);
      handler = handler.next;
    }
    return listeners;
  }
  throw new ERR_INVALID_ARG_TYPE('emitter',
                                 ['EventEmitter', 'EventTarget'],
                                 emitterOrTarget);
}
 
/**
 * Creates a `Promise` that is fulfilled when the emitter
 * emits the given event.
 * @param {EventEmitter} emitter
 * @param {string} name
 * @param {{ signal: AbortSignal; }} [options]
 * @returns {Promise}
 */
async function once(emitter, name, options = {}) {
  const signal = options?.signal;
  validateAbortSignal(signal, 'options.signal');
  if (signal?.aborted)
    throw new AbortError(undefined, { cause: signal?.reason });
  return new Promise((resolve, reject) => {
    const errorListener = (err) => {
      emitter.removeListener(name, resolver);
      if (signal != null) {
        eventTargetAgnosticRemoveListener(signal, 'abort', abortListener);
      }
      reject(err);
    };
    const resolver = (...args) => {
      if (typeof emitter.removeListener === 'function') {
        emitter.removeListener('error', errorListener);
      }
      if (signal != null) {
        eventTargetAgnosticRemoveListener(signal, 'abort', abortListener);
      }
      resolve(args);
    };
    eventTargetAgnosticAddListener(emitter, name, resolver, { once: true });
    if (name !== 'error' && typeof emitter.once === 'function') {
      emitter.once('error', errorListener);
    }
    function abortListener() {
      eventTargetAgnosticRemoveListener(emitter, name, resolver);
      eventTargetAgnosticRemoveListener(emitter, 'error', errorListener);
      reject(new AbortError(undefined, { cause: signal?.reason }));
    }
    if (signal != null) {
      eventTargetAgnosticAddListener(
        signal, 'abort', abortListener, { once: true });
    }
  });
}
 
const AsyncIteratorPrototype = ObjectGetPrototypeOf(
  ObjectGetPrototypeOf(async function* () {}).prototype);
 
function createIterResult(value, done) {
  return { value, done };
}
 
function eventTargetAgnosticRemoveListener(emitter, name, listener, flags) {
  if (typeof emitter.removeListener === 'function') {
    emitter.removeListener(name, listener);
  } else if (typeof emitter.removeEventListener === 'function') {
    emitter.removeEventListener(name, listener, flags);
  } else {
    throw new ERR_INVALID_ARG_TYPE('emitter', 'EventEmitter', emitter);
  }
}
 
function eventTargetAgnosticAddListener(emitter, name, listener, flags) {
  if (typeof emitter.on === 'function') {
    if (flags?.once) {
      emitter.once(name, listener);
    } else {
      emitter.on(name, listener);
    }
  } else if (typeof emitter.addEventListener === 'function') {
    // EventTarget does not have `error` event semantics like Node
    // EventEmitters, we do not listen to `error` events here.
    emitter.addEventListener(name, (arg) => { listener(arg); }, flags);
  } else {
    throw new ERR_INVALID_ARG_TYPE('emitter', 'EventEmitter', emitter);
  }
}
 
/**
 * Returns an `AsyncIterator` that iterates `event` events.
 * @param {EventEmitter} emitter
 * @param {string | symbol} event
 * @param {{ signal: AbortSignal; }} [options]
 * @returns {AsyncIterator}
 */
function on(emitter, event, options) {
  const signal = options?.signal;
  validateAbortSignal(signal, 'options.signal');
  if (signal?.aborted)
    throw new AbortError(undefined, { cause: signal?.reason });
 
  const unconsumedEvents = [];
  const unconsumedPromises = [];
  let error = null;
  let finished = false;
 
  const iterator = ObjectSetPrototypeOf({
    next() {
      // First, we consume all unread events
      const value = unconsumedEvents.shift();
      if (value) {
        return PromiseResolve(createIterResult(value, false));
      }
 
      // Then we error, if an error happened
      // This happens one time if at all, because after 'error'
      // we stop listening
      if (error) {
        const p = PromiseReject(error);
        // Only the first element errors
        error = null;
        return p;
      }
 
      // If the iterator is finished, resolve to done
      if (finished) {
        return PromiseResolve(createIterResult(undefined, true));
      }
 
      // Wait until an event happens
      return new Promise(function(resolve, reject) {
        unconsumedPromises.push({ resolve, reject });
      });
    },
 
    return() {
      eventTargetAgnosticRemoveListener(emitter, event, eventHandler);
      eventTargetAgnosticRemoveListener(emitter, 'error', errorHandler);
 
      if (signal) {
        eventTargetAgnosticRemoveListener(
          signal,
          'abort',
          abortListener,
          { once: true });
      }
 
      finished = true;
 
      for (const promise of unconsumedPromises) {
        promise.resolve(createIterResult(undefined, true));
      }
 
      return PromiseResolve(createIterResult(undefined, true));
    },
 
    throw(err) {
      if (!err || !(err instanceof Error)) {
        throw new ERR_INVALID_ARG_TYPE('EventEmitter.AsyncIterator',
                                       'Error', err);
      }
      error = err;
      eventTargetAgnosticRemoveListener(emitter, event, eventHandler);
      eventTargetAgnosticRemoveListener(emitter, 'error', errorHandler);
    },
 
    [SymbolAsyncIterator]() {
      return this;
    }
  }, AsyncIteratorPrototype);
 
  eventTargetAgnosticAddListener(emitter, event, eventHandler);
  if (event !== 'error' && typeof emitter.on === 'function') {
    emitter.on('error', errorHandler);
  }
 
  if (signal) {
    eventTargetAgnosticAddListener(
      signal,
      'abort',
      abortListener,
      { once: true });
  }
 
  return iterator;
 
  function abortListener() {
    errorHandler(new AbortError(undefined, { cause: signal?.reason }));
  }
 
  function eventHandler(...args) {
    const promise = ArrayPrototypeShift(unconsumedPromises);
    if (promise) {
      promise.resolve(createIterResult(args, false));
    } else {
      unconsumedEvents.push(args);
    }
  }
 
  function errorHandler(err) {
    finished = true;
 
    const toError = ArrayPrototypeShift(unconsumedPromises);
 
    if (toError) {
      toError.reject(err);
    } else {
      // The next time we call next()
      error = err;
    }
 
    iterator.return();
  }
}