lexer.js
   1  let source, pos, end;
   2  let openTokenDepth,
   3    templateDepth,
   4    lastTokenPos,
   5    lastSlashWasDivision,
   6    templateStack,
   7    templateStackDepth,
   8    openTokenPosStack,
   9    openClassPosStack,
  10    nextBraceIsClass,
  11    starExportMap,
  12    lastStarExportSpecifier,
  13    _exports,
  14    reexports;
  15  
  16  function resetState () {
  17    openTokenDepth = 0;
  18    templateDepth = -1;
  19    lastTokenPos = -1;
  20    lastSlashWasDivision = false;
  21    templateStack = new Array(1024);
  22    templateStackDepth = 0;
  23    openTokenPosStack = new Array(1024);
  24    openClassPosStack = new Array(1024);
  25    nextBraceIsClass = false;
  26    starExportMap = Object.create(null);
  27    lastStarExportSpecifier = null;
  28  
  29    _exports = new Set();
  30    reexports = new Set();
  31  }
  32  
  33  // RequireType
  34  const Import = 0;
  35  const ExportAssign = 1;
  36  const ExportStar = 2;
  37  
  38  const strictReserved = new Set(['implements', 'interface', 'let', 'package', 'private', 'protected', 'public', 'static', 'yield', 'enum']);
  39  
  40  function parseCJS (source, name = '@') {
  41    resetState();
  42    try {
  43      parseSource(source);
  44    }
  45    catch (e) {
  46      e.message += `\n  at ${name}:${source.slice(0, pos).split('\n').length}:${pos - source.lastIndexOf('\n', pos - 1)}`;
  47      e.loc = pos;
  48      throw e;
  49    }
  50    const result = { exports: [..._exports], reexports: [...reexports] };
  51    resetState();
  52    return result;
  53  }
  54  
  55  function addExport (name) {
  56    if (!strictReserved.has(name))
  57      _exports.add(name);
  58  }
  59  
  60  function parseSource (cjsSource) {
  61    source = cjsSource;
  62    pos = -1;
  63    end = source.length - 1;
  64    let ch = 0;
  65  
  66    // Handle #!
  67    if (source.charCodeAt(0) === 35/*#*/ && source.charCodeAt(1) === 33/*!*/) {
  68      if (source.length === 2)
  69        return true;
  70      pos += 2;
  71      while (pos++ < end) {
  72        ch = source.charCodeAt(pos);
  73        if (ch === 10/*\n*/ || ch === 13/*\r*/)
  74          break;
  75      }
  76    }
  77  
  78    while (pos++ < end) {
  79      ch = source.charCodeAt(pos);
  80  
  81      if (ch === 32 || ch < 14 && ch > 8)
  82        continue;
  83  
  84      if (openTokenDepth === 0) {
  85        switch (ch) {
  86          case 105/*i*/:
  87            if (source.startsWith('mport', pos + 1) && keywordStart(pos))
  88              throwIfImportStatement();
  89            lastTokenPos = pos;
  90            continue;
  91          case 114/*r*/:
  92            const startPos = pos;
  93            if (tryParseRequire(Import) && keywordStart(startPos))
  94              tryBacktrackAddStarExportBinding(startPos - 1);
  95            lastTokenPos = pos;
  96            continue;
  97          case 95/*_*/:
  98            if (source.startsWith('_export', pos + 1) && (keywordStart(pos) || source.charCodeAt(pos - 1) === 46/*.*/)) {
  99              pos += 8;
 100              if (source.startsWith('Star', pos))
 101                pos += 4;
 102              if (source.charCodeAt(pos) === 40/*(*/) {
 103                openTokenPosStack[openTokenDepth++] = lastTokenPos;
 104                if (source.charCodeAt(++pos) === 114/*r*/)
 105                  tryParseRequire(ExportStar);
 106              }
 107            }
 108            lastTokenPos = pos;
 109            continue;
 110        }
 111      }
 112  
 113      switch (ch) {
 114        case 101/*e*/:
 115          if (source.startsWith('xport', pos + 1) && keywordStart(pos)) {
 116            if (source.charCodeAt(pos + 6) === 115/*s*/)
 117              tryParseExportsDotAssign(false);
 118            else if (openTokenDepth === 0)
 119              throwIfExportStatement();
 120          }
 121          break;
 122        case 99/*c*/:
 123          if (keywordStart(pos) && source.startsWith('lass', pos + 1) && isBrOrWs(source.charCodeAt(pos + 5)))
 124            nextBraceIsClass = true;
 125          break;
 126        case 109/*m*/:
 127          if (source.startsWith('odule', pos + 1) && keywordStart(pos))
 128            tryParseModuleExportsDotAssign();
 129          break;
 130        case 79/*O*/:
 131          if (source.startsWith('bject', pos + 1) && keywordStart(pos))
 132            tryParseObjectDefineOrKeys(openTokenDepth === 0);
 133          break;
 134        case 40/*(*/:
 135          openTokenPosStack[openTokenDepth++] = lastTokenPos;
 136          break;
 137        case 41/*)*/:
 138          if (openTokenDepth === 0)
 139            throw new Error('Unexpected closing bracket.');
 140          openTokenDepth--;
 141          break;
 142        case 123/*{*/:
 143          openClassPosStack[openTokenDepth] = nextBraceIsClass;
 144          nextBraceIsClass = false;
 145          openTokenPosStack[openTokenDepth++] = lastTokenPos;
 146          break;
 147        case 125/*}*/:
 148          if (openTokenDepth === 0)
 149            throw new Error('Unexpected closing brace.');
 150          if (openTokenDepth-- === templateDepth) {
 151            templateDepth = templateStack[--templateStackDepth];
 152            templateString();
 153          }
 154          else {
 155            if (templateDepth !== -1 && openTokenDepth < templateDepth)
 156              throw new Error('Unexpected closing brace.');
 157          }
 158          break;
 159        case 60/*>*/:
 160          // TODO: <!-- XML comment support
 161          break;
 162        case 39/*'*/:
 163          singleQuoteString();
 164          break;
 165        case 34/*"*/:
 166          doubleQuoteString();
 167          break;
 168        case 47/*/*/: {
 169          const next_ch = source.charCodeAt(pos + 1);
 170          if (next_ch === 47/*/*/) {
 171            lineComment();
 172            // dont update lastToken
 173            continue;
 174          }
 175          else if (next_ch === 42/***/) {
 176            blockComment();
 177            // dont update lastToken
 178            continue;
 179          }
 180          else {
 181            // Division / regex ambiguity handling based on checking backtrack analysis of:
 182            // - what token came previously (lastToken)
 183            // - if a closing brace or paren, what token came before the corresponding
 184            //   opening brace or paren (lastOpenTokenIndex)
 185            const lastToken = source.charCodeAt(lastTokenPos);
 186            if (isExpressionPunctuator(lastToken) &&
 187                !(lastToken === 46/*.*/ && (source.charCodeAt(lastTokenPos - 1) >= 48/*0*/ && source.charCodeAt(lastTokenPos - 1) <= 57/*9*/)) &&
 188                !(lastToken === 43/*+*/ && source.charCodeAt(lastTokenPos - 1) === 43/*+*/) && !(lastToken === 45/*-*/ && source.charCodeAt(lastTokenPos - 1) === 45/*-*/) ||
 189                lastToken === 41/*)*/ && isParenKeyword(openTokenPosStack[openTokenDepth]) ||
 190                lastToken === 125/*}*/ && (isExpressionTerminator(openTokenPosStack[openTokenDepth]) || openClassPosStack[openTokenDepth]) ||
 191                lastToken === 47/*/*/ && lastSlashWasDivision ||
 192                isExpressionKeyword(lastTokenPos) ||
 193                !lastToken) {
 194              regularExpression();
 195              lastSlashWasDivision = false;
 196            }
 197            else {
 198              lastSlashWasDivision = true;
 199            }
 200          }
 201          break;
 202        }
 203        case 96/*`*/:
 204          templateString();
 205          break;
 206      }
 207      lastTokenPos = pos;
 208    }
 209  
 210    if (templateDepth !== -1)
 211      throw new Error('Unterminated template.');
 212  
 213    if (openTokenDepth)
 214      throw new Error('Unterminated braces.');
 215  }
 216  
 217  function tryBacktrackAddStarExportBinding (bPos) {
 218    while (source.charCodeAt(bPos) === 32/* */ && bPos >= 0)
 219      bPos--;
 220    if (source.charCodeAt(bPos) === 61/*=*/) {
 221      bPos--;
 222      while (source.charCodeAt(bPos) === 32/* */ && bPos >= 0)
 223        bPos--;
 224      let codePoint;
 225      const id_end = bPos;
 226      let identifierStart = false;
 227      while ((codePoint = codePointAtLast(bPos)) && bPos >= 0) {
 228        if (codePoint === 92/*\*/)
 229          return;
 230        if (!isIdentifierChar(codePoint, true))
 231          break;
 232        identifierStart = isIdentifierStart(codePoint, true);
 233        bPos -= codePointLen(codePoint);
 234      }
 235      if (identifierStart && source.charCodeAt(bPos) === 32/* */) {
 236        const starExportId = source.slice(bPos + 1, id_end + 1);
 237        while (source.charCodeAt(bPos) === 32/* */ && bPos >= 0)
 238          bPos--;
 239        switch (source.charCodeAt(bPos)) {
 240          case 114/*r*/:
 241            if (!source.startsWith('va', bPos - 2))
 242              return;
 243            break;
 244          case 116/*t*/:
 245            if (!source.startsWith('le', bPos - 2) && !source.startsWith('cons', bPos - 4))
 246              return;
 247            break;
 248          default: return;
 249        }
 250        starExportMap[starExportId] = lastStarExportSpecifier;
 251      }
 252    }
 253  }
 254  
 255  function tryParseObjectDefineOrKeys (keys) {
 256    pos += 6;
 257    let revertPos = pos - 1;
 258    let ch = commentWhitespace();
 259    if (ch === 46/*.*/) {
 260      pos++;
 261      ch = commentWhitespace();
 262      if (ch === 100/*d*/ && source.startsWith('efineProperty', pos + 1)) {
 263        while (true) {
 264          pos += 14;
 265          revertPos = pos - 1;
 266          ch = commentWhitespace();
 267          if (ch !== 40/*(*/) break;
 268          pos++;
 269          ch = commentWhitespace();
 270          if (!readExportsOrModuleDotExports(ch)) break;
 271          ch = commentWhitespace();
 272          if (ch !== 44/*,*/) break;
 273          pos++;
 274          ch = commentWhitespace();
 275          if (ch !== 39/*'*/ && ch !== 34/*"*/) break;
 276          let quot = ch;
 277          const exportPos = ++pos;
 278          if (!identifier() || source.charCodeAt(pos) !== quot) break;
 279          const expt = source.slice(exportPos, pos);
 280          pos++;
 281          ch = commentWhitespace();
 282          if (ch !== 44/*,*/) break;
 283          pos++;
 284          ch = commentWhitespace();
 285          if (ch !== 123/*{*/) break;
 286          pos++;
 287          ch = commentWhitespace();
 288          if (ch === 101/*e*/) {
 289            if (!source.startsWith('numerable', pos + 1)) break;
 290            pos += 10;
 291            ch = commentWhitespace();
 292            if (ch !== 58/*:*/) break;
 293            pos++;
 294            ch = commentWhitespace();
 295            if (ch !== 116/*t*/ || !source.startsWith('rue', pos + 1)) break;
 296            pos += 4;
 297            ch = commentWhitespace();
 298            if (ch !== 44) break;
 299            pos++;
 300            ch = commentWhitespace();
 301          }
 302          if (ch === 118/*v*/) {
 303            if (!source.startsWith('alue', pos + 1)) break;
 304            pos += 5;
 305            ch = commentWhitespace();
 306            if (ch !== 58/*:*/) break;
 307            pos++;
 308            addExport(expt);
 309            break;
 310          }
 311          else if (ch === 103/*g*/) {
 312            if (!source.startsWith('et', pos + 1)) break;
 313            pos += 3;
 314            ch = commentWhitespace();
 315            if (ch === 58/*:*/) {
 316              pos++;
 317              ch = commentWhitespace();
 318              if (ch !== 102/*f*/) break;
 319              if (!source.startsWith('unction', pos + 1)) break;
 320              pos += 8;
 321              let lastPos = pos;
 322              ch = commentWhitespace();
 323              if (ch !== 40 && (lastPos === pos || !identifier())) break;
 324              ch = commentWhitespace();
 325            }
 326            if (ch !== 40/*(*/) break;
 327            pos++;
 328            ch = commentWhitespace();
 329            if (ch !== 41/*)*/) break;
 330            pos++;
 331            ch = commentWhitespace();
 332            if (ch !== 123/*{*/) break;
 333            pos++;
 334            ch = commentWhitespace();
 335            if (ch !== 114/*r*/) break;
 336            if (!source.startsWith('eturn', pos + 1)) break;
 337            pos += 6;
 338            ch = commentWhitespace();
 339            if (!identifier()) break;
 340            ch = commentWhitespace();
 341            if (ch === 46/*.*/) {
 342              pos++;
 343              commentWhitespace();
 344              if (!identifier()) break;
 345              ch = commentWhitespace();
 346            }
 347            else if (ch === 91/*[*/) {
 348              pos++;
 349              ch = commentWhitespace();
 350              if (ch === 39/*'*/) singleQuoteString();
 351              else if (ch === 34/*"*/) doubleQuoteString();
 352              else break;
 353              pos++;
 354              ch = commentWhitespace();
 355              if (ch !== 93/*]*/) break;
 356              pos++;
 357              ch = commentWhitespace();
 358            }
 359            if (ch === 59/*;*/) {
 360              pos++;
 361              ch = commentWhitespace();
 362            }
 363            if (ch !== 125/*}*/) break;
 364            pos++;
 365            ch = commentWhitespace();
 366            if (ch !== 125/*}*/) break;
 367            pos++;
 368            ch = commentWhitespace();
 369            if (ch !== 41/*)*/) break;
 370            addExport(expt);
 371            return;
 372          }
 373          break;
 374        }
 375      }
 376      else if (keys && ch === 107/*k*/ && source.startsWith('eys', pos + 1)) {
 377        while (true) {
 378          pos += 4;
 379          revertPos = pos - 1;
 380          ch = commentWhitespace();
 381          if (ch !== 40/*(*/) break;
 382          pos++;
 383          ch = commentWhitespace();
 384          const id_start = pos;
 385          if (!identifier()) break;
 386          const id = source.slice(id_start, pos);
 387          ch = commentWhitespace();
 388          if (ch !== 41/*)*/) break;
 389  
 390          revertPos = pos++;
 391          ch = commentWhitespace();
 392          if (ch !== 46/*.*/) break;
 393          pos++;
 394          ch = commentWhitespace();
 395          if (ch !== 102/*f*/ || !source.startsWith('orEach', pos + 1)) break;
 396          pos += 7;
 397          ch = commentWhitespace();
 398          revertPos = pos - 1;
 399          if (ch !== 40/*(*/) break;
 400          pos++;
 401          ch = commentWhitespace();
 402          if (ch !== 102/*f*/ || !source.startsWith('unction', pos + 1)) break;
 403          pos += 8;
 404          ch = commentWhitespace();
 405          if (ch !== 40/*(*/) break;
 406          pos++;
 407          ch = commentWhitespace();
 408          const it_id_start = pos;
 409          if (!identifier()) break;
 410          const it_id = source.slice(it_id_start, pos);
 411          ch = commentWhitespace();
 412          if (ch !== 41/*)*/) break;
 413          pos++;
 414          ch = commentWhitespace();
 415          if (ch !== 123/*{*/) break;
 416          pos++;
 417          ch = commentWhitespace();
 418          if (ch !== 105/*i*/ || source.charCodeAt(pos + 1) !== 102/*f*/) break;
 419          pos += 2;
 420          ch = commentWhitespace();
 421          if (ch !== 40/*(*/) break;
 422          pos++;
 423          ch = commentWhitespace();
 424          if (!source.startsWith(it_id, pos)) break;
 425          pos += it_id.length;
 426          ch = commentWhitespace();
 427          // `if (` IDENTIFIER$2 `===` ( `'default'` | `"default"` ) `||` IDENTIFIER$2 `===` ( '__esModule' | `"__esModule"` ) `) return` `;`? |
 428          if (ch === 61/*=*/) {
 429            if (!source.startsWith('==', pos + 1)) break;
 430            pos += 3;
 431            ch = commentWhitespace();
 432            if (ch !== 34/*"*/ && ch !== 39/*'*/) break;
 433            let quot = ch;
 434            if (!source.startsWith('default', pos + 1)) break;
 435            pos += 8;
 436            ch = commentWhitespace();
 437            if (ch !== quot) break;
 438            pos += 1;
 439            ch = commentWhitespace();
 440            if (ch !== 124/*|*/ || source.charCodeAt(pos + 1) !== 124/*|*/) break;
 441            pos += 2;
 442            ch = commentWhitespace();
 443            if (source.slice(pos, pos + it_id.length) !== it_id) break;
 444            pos += it_id.length;
 445            ch = commentWhitespace();
 446            if (ch !== 61/*=*/ || source.slice(pos + 1, pos + 3) !== '==') break;
 447            pos += 3;
 448            ch = commentWhitespace();
 449            if (ch !== 34/*"*/ && ch !== 39/*'*/) break;
 450            quot = ch;
 451            if (!source.startsWith('__esModule', pos + 1)) break;
 452            pos += 11;
 453            ch = commentWhitespace();
 454            if (ch !== quot) break;
 455            pos += 1;
 456            ch = commentWhitespace();
 457            if (ch !== 41/*)*/) break;
 458            pos += 1;
 459            ch = commentWhitespace();
 460            if (ch !== 114/*r*/ || !source.startsWith('eturn', pos + 1)) break;
 461            pos += 6;
 462            ch = commentWhitespace();
 463            if (ch === 59/*;*/)
 464              pos++;
 465            ch = commentWhitespace();
 466          }
 467          // `if (` IDENTIFIER$2 `!==` ( `'default'` | `"default"` ) `)`
 468          else if (ch === 33/*!*/) {
 469            if (!source.startsWith('==', pos + 1)) break;
 470            pos += 3;
 471            ch = commentWhitespace();
 472            if (ch !== 34/*"*/ && ch !== 39/*'*/) break;
 473            const quot = ch;
 474            if (!source.startsWith('default', pos + 1)) break;
 475            pos += 8;
 476            ch = commentWhitespace();
 477            if (ch !== quot) break;
 478            pos += 1;
 479            ch = commentWhitespace();
 480            if (ch !== 41/*)*/) break;
 481            pos += 1;
 482            ch = commentWhitespace();
 483          }
 484          else break;
 485  
 486          // `if (` IDENTIFIER$2 `in` EXPORTS_IDENTIFIER `&&` EXPORTS_IDENTIFIER `[` IDENTIFIER$2 `] ===` IDENTIFIER$1 `[` IDENTIFIER$2 `]) return` `;`?
 487          if (ch === 105/*i*/ && source.charCodeAt(pos + 1) === 102/*f*/) {
 488            pos += 2;
 489            ch = commentWhitespace();
 490            if (ch !== 40/*(*/) break;
 491            pos++;
 492            ch = commentWhitespace();
 493            if (!source.startsWith(it_id, pos)) break;
 494            pos += it_id.length;
 495            ch = commentWhitespace();
 496            if (ch !== 105/*i*/ || !source.startsWith('n ', pos + 1)) break;
 497            pos += 3;
 498            ch = commentWhitespace();
 499            if (!readExportsOrModuleDotExports(ch)) break;
 500            ch = commentWhitespace();
 501            if (ch !== 38/*&*/ || source.charCodeAt(pos + 1) !== 38/*&*/) break;
 502            pos += 2;
 503            ch = commentWhitespace();
 504            if (!readExportsOrModuleDotExports(ch)) break;
 505            ch = commentWhitespace();
 506            if (ch !== 91/*[*/) break;
 507            pos++;
 508            ch = commentWhitespace();
 509            if (!source.startsWith(it_id, pos)) break;
 510            pos += it_id.length;
 511            ch = commentWhitespace();
 512            if (ch !== 93/*]*/) break;
 513            pos++;
 514            ch = commentWhitespace();
 515            if (ch !== 61/*=*/ || !source.startsWith('==', pos + 1)) break;
 516            pos += 3;
 517            ch = commentWhitespace();
 518            if (!source.startsWith(id, pos)) break;
 519            pos += id.length;
 520            ch = commentWhitespace();
 521            if (ch !== 91/*[*/) break;
 522            pos++;
 523            ch = commentWhitespace();
 524            if (!source.startsWith(it_id, pos)) break;
 525            pos += it_id.length;
 526            ch = commentWhitespace();
 527            if (ch !== 93/*]*/) break;
 528            pos++;
 529            ch = commentWhitespace();
 530            if (ch !== 41/*)*/) break;
 531            pos++;
 532            ch = commentWhitespace();
 533            if (ch !== 114/*r*/ || !source.startsWith('eturn', pos + 1)) break;
 534            pos += 6;
 535            ch = commentWhitespace();
 536            if (ch === 59/*;*/)
 537              pos++;
 538            ch = commentWhitespace();
 539          }
 540  
 541          // EXPORTS_IDENTIFIER `[` IDENTIFIER$2 `] =` IDENTIFIER$1 `[` IDENTIFIER$2 `]`
 542          if (readExportsOrModuleDotExports(ch)) {
 543            ch = commentWhitespace();
 544            if (ch !== 91/*[*/) break;
 545            pos++;
 546            ch = commentWhitespace();
 547            if (source.slice(pos, pos + it_id.length) !== it_id) break;
 548            pos += it_id.length;
 549            ch = commentWhitespace();
 550            if (ch !== 93/*]*/) break;
 551            pos++;
 552            ch = commentWhitespace();
 553            if (ch !== 61/*=*/) break;
 554            pos++;
 555            ch = commentWhitespace();
 556            if (source.slice(pos, pos + id.length) !== id) break;
 557            pos += id.length;
 558            ch = commentWhitespace();
 559            if (ch !== 91/*[*/) break;
 560            pos++;
 561            ch = commentWhitespace();
 562            if (source.slice(pos, pos + it_id.length) !== it_id) break;
 563            pos += it_id.length;
 564            ch = commentWhitespace();
 565            if (ch !== 93/*]*/) break;
 566            pos++;
 567            ch = commentWhitespace();
 568            if (ch === 59/*;*/) {
 569              pos++;
 570              ch = commentWhitespace();
 571            }
 572          }
 573          // `Object.defineProperty(` EXPORTS_IDENTIFIER `, ` IDENTIFIER$2 `, { enumerable: true, get: function () { return ` IDENTIFIER$1 `[` IDENTIFIER$2 `]; } })`
 574          else if (ch === 79/*O*/) {
 575            if (source.slice(pos + 1, pos + 6) !== 'bject') break;
 576            pos += 6;
 577            ch = commentWhitespace();
 578            if (ch !== 46/*.*/) break;
 579            pos++;
 580            ch = commentWhitespace();
 581            if (ch !== 100/*d*/ || !source.startsWith('efineProperty', pos + 1)) break;
 582            pos += 14;
 583            ch = commentWhitespace();
 584            if (ch !== 40/*(*/) break;
 585            pos++;
 586            ch = commentWhitespace();
 587            if (!readExportsOrModuleDotExports(ch)) break;
 588            ch = commentWhitespace();
 589            if (ch !== 44/*,*/) break;
 590            pos++;
 591            ch = commentWhitespace();
 592            if (!source.startsWith(it_id, pos)) break;
 593            pos += it_id.length;
 594            ch = commentWhitespace();
 595            if (ch !== 44/*,*/) break;
 596            pos++;
 597            ch = commentWhitespace();
 598            if (ch !== 123/*{*/) break;
 599            pos++;
 600            ch = commentWhitespace();
 601            if (ch !== 101/*e*/ || !source.startsWith('numerable', pos + 1)) break;
 602            pos += 10;
 603            ch = commentWhitespace();
 604            if (ch !== 58/*:*/) break;
 605            pos++;
 606            ch = commentWhitespace();
 607            if (ch !== 116/*t*/ && !source.startsWith('rue', pos + 1)) break;
 608            pos += 4;
 609            ch = commentWhitespace();
 610            if (ch !== 44/*,*/) break;
 611            pos++;
 612            ch = commentWhitespace();
 613            if (ch !== 103/*g*/ || !source.startsWith('et', pos + 1)) break;
 614            pos += 3;
 615            ch = commentWhitespace();
 616            if (ch !== 58/*:*/) break;
 617            pos++;
 618            ch = commentWhitespace();
 619            if (ch !== 102/*f*/ || !source.startsWith('unction', pos + 1)) break;
 620            pos += 8;
 621            ch = commentWhitespace();
 622            if (ch !== 40/*(*/) break;
 623            pos++;
 624            ch = commentWhitespace();
 625            if (ch !== 41/*)*/) break;
 626            pos++;
 627            ch = commentWhitespace();
 628            if (ch !== 123/*{*/) break;
 629            pos++;
 630            ch = commentWhitespace();
 631            if (ch !== 114/*r*/ || !source.startsWith('eturn', pos + 1)) break;
 632            pos += 6;
 633            ch = commentWhitespace();
 634            if (!source.startsWith(id, pos)) break;
 635            pos += id.length;
 636            ch = commentWhitespace();
 637            if (ch !== 91/*[*/) break;
 638            pos++;
 639            ch = commentWhitespace();
 640            if (!source.startsWith(it_id, pos)) break;
 641            pos += it_id.length;
 642            ch = commentWhitespace();
 643            if (ch !== 93/*]*/) break;
 644            pos++;
 645            ch = commentWhitespace();
 646            if (ch === 59/*;*/) {
 647              pos++;
 648              ch = commentWhitespace();
 649            }
 650            if (ch !== 125/*}*/) break;
 651            pos++;
 652            ch = commentWhitespace();
 653            if (ch !== 125/*}*/) break;
 654            pos++;
 655            ch = commentWhitespace();
 656            if (ch !== 41/*)*/) break;
 657            pos++;
 658            ch = commentWhitespace();
 659            if (ch === 59/*;*/) {
 660              pos++;
 661              ch = commentWhitespace();
 662            }
 663          }
 664          else break;
 665  
 666          if (ch !== 125/*}*/) break;
 667          pos++;
 668          ch = commentWhitespace();
 669          if (ch !== 41/*)*/) break;
 670  
 671          const starExportSpecifier = starExportMap[id];
 672          if (starExportSpecifier) {
 673            reexports.add(starExportSpecifier);
 674            pos = revertPos;
 675            return;
 676          }
 677          return;
 678        }
 679      }
 680    }
 681    pos = revertPos;
 682  }
 683  
 684  function readExportsOrModuleDotExports (ch) {
 685    const revertPos = pos;
 686    if (ch === 109/*m*/ && source.startsWith('odule', pos + 1)) {
 687      pos += 6;
 688      ch = commentWhitespace();
 689      if (ch !== 46/*.*/) {
 690        pos = revertPos;
 691        return false;
 692      }
 693      pos++;
 694      ch = commentWhitespace();
 695    }
 696    if (ch === 101/*e*/ && source.startsWith('xports', pos + 1)) {
 697      pos += 7;
 698      return true;
 699    }
 700    else {
 701      pos = revertPos;
 702      return false;
 703    }
 704  }
 705  
 706  function tryParseModuleExportsDotAssign () {
 707    pos += 6;
 708    const revertPos = pos - 1;
 709    let ch = commentWhitespace();
 710    if (ch === 46/*.*/) {
 711      pos++;
 712      ch = commentWhitespace();
 713      if (ch === 101/*e*/ && source.startsWith('xports', pos + 1)) {
 714        tryParseExportsDotAssign(true);
 715        return;
 716      }
 717    }
 718    pos = revertPos;
 719  }
 720  
 721  function tryParseExportsDotAssign (assign) {
 722    pos += 7;
 723    const revertPos = pos - 1;
 724    let ch = commentWhitespace();
 725    switch (ch) {
 726      // exports.asdf
 727      case 46/*.*/: {
 728        pos++;
 729        ch = commentWhitespace();
 730        const startPos = pos;
 731        if (identifier()) {
 732          const endPos = pos;
 733          ch = commentWhitespace();
 734          if (ch === 61/*=*/) {
 735            addExport(source.slice(startPos, endPos));
 736            return;
 737          }
 738        }
 739        break;
 740      }
 741      // exports['asdf']
 742      case 91/*[*/: {
 743        pos++;
 744        ch = commentWhitespace();
 745        if (ch === 39/*'*/ || ch === 34/*"*/) {
 746          pos++;
 747          const startPos = pos;
 748          if (identifier() && source.charCodeAt(pos) === ch) {
 749            const endPos = pos++;
 750            ch = commentWhitespace();
 751            if (ch !== 93/*]*/)
 752              break;
 753            pos++;
 754            ch = commentWhitespace();
 755            if (ch !== 61/*=*/)
 756              break;
 757            addExport(source.slice(startPos, endPos));
 758          }
 759        }
 760        break;
 761      }
 762      // module.exports =
 763      case 61/*=*/: {
 764        if (assign) {
 765          if (reexports.size)
 766            reexports = new Set();
 767          pos++;
 768          ch = commentWhitespace();
 769          // { ... }
 770          if (ch === 123/*{*/) {
 771            tryParseLiteralExports();
 772            return;
 773          }
 774  
 775          // require('...')
 776          if (ch === 114/*r*/)
 777            tryParseRequire(ExportAssign);
 778        }
 779      }
 780    }
 781    pos = revertPos;
 782  }
 783  
 784  function tryParseRequire (requireType) {
 785    // require('...')
 786    const revertPos = pos;
 787    if (source.startsWith('equire', pos + 1)) {
 788      pos += 7;
 789      let ch = commentWhitespace();
 790      if (ch === 40/*(*/) {
 791        pos++;
 792        ch = commentWhitespace();
 793        const reexportStart = pos + 1;
 794        if (ch === 39/*'*/) {
 795          singleQuoteString();
 796          const reexportEnd = pos++;
 797          ch = commentWhitespace();
 798          if (ch === 41/*)*/) {
 799            switch (requireType) {
 800              case ExportAssign:
 801                reexports.add(source.slice(reexportStart, reexportEnd));
 802                return true;
 803              case ExportStar:
 804                reexports.add(source.slice(reexportStart, reexportEnd));
 805                return true;
 806              default:
 807                lastStarExportSpecifier = source.slice(reexportStart, reexportEnd);
 808                return true;
 809            }
 810          }
 811        }
 812        else if (ch === 34/*"*/) {
 813          doubleQuoteString();
 814          const reexportEnd = pos++;
 815          ch = commentWhitespace();
 816          if (ch === 41/*)*/) {
 817            switch (requireType) {
 818              case ExportAssign:
 819                reexports.add(source.slice(reexportStart, reexportEnd));
 820                return true;
 821              case ExportStar:
 822                reexports.add(source.slice(reexportStart, reexportEnd));
 823                return true;
 824              default:
 825                lastStarExportSpecifier = source.slice(reexportStart, reexportEnd);
 826                return true;
 827            }
 828          }
 829        }
 830      }
 831      pos = revertPos;
 832    }
 833    return false;
 834  }
 835  
 836  function tryParseLiteralExports () {
 837    const revertPos = pos - 1;
 838    while (pos++ < end) {
 839      let ch = commentWhitespace();
 840      const startPos = pos;
 841      if (identifier()) {
 842        const endPos = pos;
 843        ch = commentWhitespace();
 844        if (ch === 58/*:*/) {
 845          pos++;
 846          ch = commentWhitespace();
 847          // nothing more complex than identifier expressions for now
 848          if (!identifier()) {
 849            pos = revertPos;
 850            return;
 851          }
 852          ch = source.charCodeAt(pos);
 853        }
 854        addExport(source.slice(startPos, endPos));
 855      }
 856      else if (ch === 46/*.*/ && source.startsWith('..', pos + 1)) {
 857        pos += 3;
 858        if (source.charCodeAt(pos) === 114/*r*/ && tryParseRequire(ExportAssign)) {
 859          pos++;
 860        }
 861        else if (!identifier()) {
 862          pos = revertPos;
 863          return;
 864        }
 865        ch = commentWhitespace();
 866      }
 867      else if (ch === 39/*'*/ || ch === 34/*"*/) {
 868        const startPos = ++pos;
 869        if (identifier() && source.charCodeAt(pos) === ch) {
 870          const endPos = pos++;
 871          ch = commentWhitespace();
 872          if (ch === 58/*:*/) {
 873            pos++;
 874            ch = commentWhitespace();
 875            // nothing more complex than identifier expressions for now
 876            if (!identifier()) {
 877              pos = revertPos;
 878              return;
 879            }
 880            ch = source.charCodeAt(pos);
 881            addExport(source.slice(startPos, endPos));
 882          }
 883        }
 884      }
 885      else {
 886        pos = revertPos;
 887        return;
 888      }
 889  
 890      if (ch === 125/*}*/)
 891        return;
 892  
 893      if (ch !== 44/*,*/) {
 894        pos = revertPos;
 895        return;
 896      }
 897    }
 898  }
 899  
 900  // --- Extracted from AcornJS ---
 901  //(https://github.com/acornjs/acorn/blob/master/acorn/src/identifier.js#L23
 902  //
 903  // MIT License
 904  
 905  // Copyright (C) 2012-2018 by various contributors (see AUTHORS)
 906  
 907  // Permission is hereby granted, free of charge, to any person obtaining a copy
 908  // of this software and associated documentation files (the "Software"), to deal
 909  // in the Software without restriction, including without limitation the rights
 910  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 911  // copies of the Software, and to permit persons to whom the Software is
 912  // furnished to do so, subject to the following conditions:
 913  
 914  // The above copyright notice and this permission notice shall be included in
 915  // all copies or substantial portions of the Software.
 916  
 917  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 918  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 919  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 920  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 921  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 922  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 923  // THE SOFTWARE.
 924  
 925  // ## Character categories
 926  
 927  // Big ugly regular expressions that match characters in the
 928  // whitespace, identifier, and identifier-start categories. These
 929  // are only applied when a character is found to actually have a
 930  // code point above 128.
 931  // Generated by `bin/generate-identifier-regex.js`.
 932  let nonASCIIidentifierStartChars = "\xaa\xb5\xba\xc0-\xd6\xd8-\xf6\xf8-\u02c1\u02c6-\u02d1\u02e0-\u02e4\u02ec\u02ee\u0370-\u0374\u0376\u0377\u037a-\u037d\u037f\u0386\u0388-\u038a\u038c\u038e-\u03a1\u03a3-\u03f5\u03f7-\u0481\u048a-\u052f\u0531-\u0556\u0559\u0560-\u0588\u05d0-\u05ea\u05ef-\u05f2\u0620-\u064a\u066e\u066f\u0671-\u06d3\u06d5\u06e5\u06e6\u06ee\u06ef\u06fa-\u06fc\u06ff\u0710\u0712-\u072f\u074d-\u07a5\u07b1\u07ca-\u07ea\u07f4\u07f5\u07fa\u0800-\u0815\u081a\u0824\u0828\u0840-\u0858\u0860-\u086a\u08a0-\u08b4\u08b6-\u08c7\u0904-\u0939\u093d\u0950\u0958-\u0961\u0971-\u0980\u0985-\u098c\u098f\u0990\u0993-\u09a8\u09aa-\u09b0\u09b2\u09b6-\u09b9\u09bd\u09ce\u09dc\u09dd\u09df-\u09e1\u09f0\u09f1\u09fc\u0a05-\u0a0a\u0a0f\u0a10\u0a13-\u0a28\u0a2a-\u0a30\u0a32\u0a33\u0a35\u0a36\u0a38\u0a39\u0a59-\u0a5c\u0a5e\u0a72-\u0a74\u0a85-\u0a8d\u0a8f-\u0a91\u0a93-\u0aa8\u0aaa-\u0ab0\u0ab2\u0ab3\u0ab5-\u0ab9\u0abd\u0ad0\u0ae0\u0ae1\u0af9\u0b05-\u0b0c\u0b0f\u0b10\u0b13-\u0b28\u0b2a-\u0b30\u0b32\u0b33\u0b35-\u0b39\u0b3d\u0b5c\u0b5d\u0b5f-\u0b61\u0b71\u0b83\u0b85-\u0b8a\u0b8e-\u0b90\u0b92-\u0b95\u0b99\u0b9a\u0b9c\u0b9e\u0b9f\u0ba3\u0ba4\u0ba8-\u0baa\u0bae-\u0bb9\u0bd0\u0c05-\u0c0c\u0c0e-\u0c10\u0c12-\u0c28\u0c2a-\u0c39\u0c3d\u0c58-\u0c5a\u0c60\u0c61\u0c80\u0c85-\u0c8c\u0c8e-\u0c90\u0c92-\u0ca8\u0caa-\u0cb3\u0cb5-\u0cb9\u0cbd\u0cde\u0ce0\u0ce1\u0cf1\u0cf2\u0d04-\u0d0c\u0d0e-\u0d10\u0d12-\u0d3a\u0d3d\u0d4e\u0d54-\u0d56\u0d5f-\u0d61\u0d7a-\u0d7f\u0d85-\u0d96\u0d9a-\u0db1\u0db3-\u0dbb\u0dbd\u0dc0-\u0dc6\u0e01-\u0e30\u0e32\u0e33\u0e40-\u0e46\u0e81\u0e82\u0e84\u0e86-\u0e8a\u0e8c-\u0ea3\u0ea5\u0ea7-\u0eb0\u0eb2\u0eb3\u0ebd\u0ec0-\u0ec4\u0ec6\u0edc-\u0edf\u0f00\u0f40-\u0f47\u0f49-\u0f6c\u0f88-\u0f8c\u1000-\u102a\u103f\u1050-\u1055\u105a-\u105d\u1061\u1065\u1066\u106e-\u1070\u1075-\u1081\u108e\u10a0-\u10c5\u10c7\u10cd\u10d0-\u10fa\u10fc-\u1248\u124a-\u124d\u1250-\u1256\u1258\u125a-\u125d\u1260-\u1288\u128a-\u128d\u1290-\u12b0\u12b2-\u12b5\u12b8-\u12be\u12c0\u12c2-\u12c5\u12c8-\u12d6\u12d8-\u1310\u1312-\u1315\u1318-\u135a\u1380-\u138f\u13a0-\u13f5\u13f8-\u13fd\u1401-\u166c\u166f-\u167f\u1681-\u169a\u16a0-\u16ea\u16ee-\u16f8\u1700-\u170c\u170e-\u1711\u1720-\u1731\u1740-\u1751\u1760-\u176c\u176e-\u1770\u1780-\u17b3\u17d7\u17dc\u1820-\u1878\u1880-\u18a8\u18aa\u18b0-\u18f5\u1900-\u191e\u1950-\u196d\u1970-\u1974\u1980-\u19ab\u19b0-\u19c9\u1a00-\u1a16\u1a20-\u1a54\u1aa7\u1b05-\u1b33\u1b45-\u1b4b\u1b83-\u1ba0\u1bae\u1baf\u1bba-\u1be5\u1c00-\u1c23\u1c4d-\u1c4f\u1c5a-\u1c7d\u1c80-\u1c88\u1c90-\u1cba\u1cbd-\u1cbf\u1ce9-\u1cec\u1cee-\u1cf3\u1cf5\u1cf6\u1cfa\u1d00-\u1dbf\u1e00-\u1f15\u1f18-\u1f1d\u1f20-\u1f45\u1f48-\u1f4d\u1f50-\u1f57\u1f59\u1f5b\u1f5d\u1f5f-\u1f7d\u1f80-\u1fb4\u1fb6-\u1fbc\u1fbe\u1fc2-\u1fc4\u1fc6-\u1fcc\u1fd0-\u1fd3\u1fd6-\u1fdb\u1fe0-\u1fec\u1ff2-\u1ff4\u1ff6-\u1ffc\u2071\u207f\u2090-\u209c\u2102\u2107\u210a-\u2113\u2115\u2118-\u211d\u2124\u2126\u2128\u212a-\u2139\u213c-\u213f\u2145-\u2149\u214e\u2160-\u2188\u2c00-\u2c2e\u2c30-\u2c5e\u2c60-\u2ce4\u2ceb-\u2cee\u2cf2\u2cf3\u2d00-\u2d25\u2d27\u2d2d\u2d30-\u2d67\u2d6f\u2d80-\u2d96\u2da0-\u2da6\u2da8-\u2dae\u2db0-\u2db6\u2db8-\u2dbe\u2dc0-\u2dc6\u2dc8-\u2dce\u2dd0-\u2dd6\u2dd8-\u2dde\u3005-\u3007\u3021-\u3029\u3031-\u3035\u3038-\u303c\u3041-\u3096\u309b-\u309f\u30a1-\u30fa\u30fc-\u30ff\u3105-\u312f\u3131-\u318e\u31a0-\u31bf\u31f0-\u31ff\u3400-\u4dbf\u4e00-\u9ffc\ua000-\ua48c\ua4d0-\ua4fd\ua500-\ua60c\ua610-\ua61f\ua62a\ua62b\ua640-\ua66e\ua67f-\ua69d\ua6a0-\ua6ef\ua717-\ua71f\ua722-\ua788\ua78b-\ua7bf\ua7c2-\ua7ca\ua7f5-\ua801\ua803-\ua805\ua807-\ua80a\ua80c-\ua822\ua840-\ua873\ua882-\ua8b3\ua8f2-\ua8f7\ua8fb\ua8fd\ua8fe\ua90a-\ua925\ua930-\ua946\ua960-\ua97c\ua984-\ua9b2\ua9cf\ua9e0-\ua9e4\ua9e6-\ua9ef\ua9fa-\ua9fe\uaa00-\uaa28\uaa40-\uaa42\uaa44-\uaa4b\uaa60-\uaa76\uaa7a\uaa7e-\uaaaf\uaab1\uaab5\uaab6\uaab9-\uaabd\uaac0\uaac2\uaadb-\uaadd\uaae0-\uaaea\uaaf2-\uaaf4\uab01-\uab06\uab09-\uab0e\uab11-\uab16\uab20-\uab26\uab28-\uab2e\uab30-\uab5a\uab5c-\uab69\uab70-\uabe2\uac00-\ud7a3\ud7b0-\ud7c6\ud7cb-\ud7fb\uf900-\ufa6d\ufa70-\ufad9\ufb00-\ufb06\ufb13-\ufb17\ufb1d\ufb1f-\ufb28\ufb2a-\ufb36\ufb38-\ufb3c\ufb3e\ufb40\ufb41\ufb43\ufb44\ufb46-\ufbb1\ufbd3-\ufd3d\ufd50-\ufd8f\ufd92-\ufdc7\ufdf0-\ufdfb\ufe70-\ufe74\ufe76-\ufefc\uff21-\uff3a\uff41-\uff5a\uff66-\uffbe\uffc2-\uffc7\uffca-\uffcf\uffd2-\uffd7\uffda-\uffdc"
 933  let nonASCIIidentifierChars = "\u200c\u200d\xb7\u0300-\u036f\u0387\u0483-\u0487\u0591-\u05bd\u05bf\u05c1\u05c2\u05c4\u05c5\u05c7\u0610-\u061a\u064b-\u0669\u0670\u06d6-\u06dc\u06df-\u06e4\u06e7\u06e8\u06ea-\u06ed\u06f0-\u06f9\u0711\u0730-\u074a\u07a6-\u07b0\u07c0-\u07c9\u07eb-\u07f3\u07fd\u0816-\u0819\u081b-\u0823\u0825-\u0827\u0829-\u082d\u0859-\u085b\u08d3-\u08e1\u08e3-\u0903\u093a-\u093c\u093e-\u094f\u0951-\u0957\u0962\u0963\u0966-\u096f\u0981-\u0983\u09bc\u09be-\u09c4\u09c7\u09c8\u09cb-\u09cd\u09d7\u09e2\u09e3\u09e6-\u09ef\u09fe\u0a01-\u0a03\u0a3c\u0a3e-\u0a42\u0a47\u0a48\u0a4b-\u0a4d\u0a51\u0a66-\u0a71\u0a75\u0a81-\u0a83\u0abc\u0abe-\u0ac5\u0ac7-\u0ac9\u0acb-\u0acd\u0ae2\u0ae3\u0ae6-\u0aef\u0afa-\u0aff\u0b01-\u0b03\u0b3c\u0b3e-\u0b44\u0b47\u0b48\u0b4b-\u0b4d\u0b55-\u0b57\u0b62\u0b63\u0b66-\u0b6f\u0b82\u0bbe-\u0bc2\u0bc6-\u0bc8\u0bca-\u0bcd\u0bd7\u0be6-\u0bef\u0c00-\u0c04\u0c3e-\u0c44\u0c46-\u0c48\u0c4a-\u0c4d\u0c55\u0c56\u0c62\u0c63\u0c66-\u0c6f\u0c81-\u0c83\u0cbc\u0cbe-\u0cc4\u0cc6-\u0cc8\u0cca-\u0ccd\u0cd5\u0cd6\u0ce2\u0ce3\u0ce6-\u0cef\u0d00-\u0d03\u0d3b\u0d3c\u0d3e-\u0d44\u0d46-\u0d48\u0d4a-\u0d4d\u0d57\u0d62\u0d63\u0d66-\u0d6f\u0d81-\u0d83\u0dca\u0dcf-\u0dd4\u0dd6\u0dd8-\u0ddf\u0de6-\u0def\u0df2\u0df3\u0e31\u0e34-\u0e3a\u0e47-\u0e4e\u0e50-\u0e59\u0eb1\u0eb4-\u0ebc\u0ec8-\u0ecd\u0ed0-\u0ed9\u0f18\u0f19\u0f20-\u0f29\u0f35\u0f37\u0f39\u0f3e\u0f3f\u0f71-\u0f84\u0f86\u0f87\u0f8d-\u0f97\u0f99-\u0fbc\u0fc6\u102b-\u103e\u1040-\u1049\u1056-\u1059\u105e-\u1060\u1062-\u1064\u1067-\u106d\u1071-\u1074\u1082-\u108d\u108f-\u109d\u135d-\u135f\u1369-\u1371\u1712-\u1714\u1732-\u1734\u1752\u1753\u1772\u1773\u17b4-\u17d3\u17dd\u17e0-\u17e9\u180b-\u180d\u1810-\u1819\u18a9\u1920-\u192b\u1930-\u193b\u1946-\u194f\u19d0-\u19da\u1a17-\u1a1b\u1a55-\u1a5e\u1a60-\u1a7c\u1a7f-\u1a89\u1a90-\u1a99\u1ab0-\u1abd\u1abf\u1ac0\u1b00-\u1b04\u1b34-\u1b44\u1b50-\u1b59\u1b6b-\u1b73\u1b80-\u1b82\u1ba1-\u1bad\u1bb0-\u1bb9\u1be6-\u1bf3\u1c24-\u1c37\u1c40-\u1c49\u1c50-\u1c59\u1cd0-\u1cd2\u1cd4-\u1ce8\u1ced\u1cf4\u1cf7-\u1cf9\u1dc0-\u1df9\u1dfb-\u1dff\u203f\u2040\u2054\u20d0-\u20dc\u20e1\u20e5-\u20f0\u2cef-\u2cf1\u2d7f\u2de0-\u2dff\u302a-\u302f\u3099\u309a\ua620-\ua629\ua66f\ua674-\ua67d\ua69e\ua69f\ua6f0\ua6f1\ua802\ua806\ua80b\ua823-\ua827\ua82c\ua880\ua881\ua8b4-\ua8c5\ua8d0-\ua8d9\ua8e0-\ua8f1\ua8ff-\ua909\ua926-\ua92d\ua947-\ua953\ua980-\ua983\ua9b3-\ua9c0\ua9d0-\ua9d9\ua9e5\ua9f0-\ua9f9\uaa29-\uaa36\uaa43\uaa4c\uaa4d\uaa50-\uaa59\uaa7b-\uaa7d\uaab0\uaab2-\uaab4\uaab7\uaab8\uaabe\uaabf\uaac1\uaaeb-\uaaef\uaaf5\uaaf6\uabe3-\uabea\uabec\uabed\uabf0-\uabf9\ufb1e\ufe00-\ufe0f\ufe20-\ufe2f\ufe33\ufe34\ufe4d-\ufe4f\uff10-\uff19\uff3f"
 934  
 935  const nonASCIIidentifierStart = new RegExp("[" + nonASCIIidentifierStartChars + "]")
 936  const nonASCIIidentifier = new RegExp("[" + nonASCIIidentifierStartChars + nonASCIIidentifierChars + "]")
 937  
 938  nonASCIIidentifierStartChars = nonASCIIidentifierChars = null
 939  
 940  // These are a run-length and offset encoded representation of the
 941  // >0xffff code points that are a valid part of identifiers. The
 942  // offset starts at 0x10000, and each pair of numbers represents an
 943  // offset to the next range, and then a size of the range. They were
 944  // generated by bin/generate-identifier-regex.js
 945  
 946  // eslint-disable-next-line comma-spacing
 947  const astralIdentifierStartCodes = [0,11,2,25,2,18,2,1,2,14,3,13,35,122,70,52,268,28,4,48,48,31,14,29,6,37,11,29,3,35,5,7,2,4,43,157,19,35,5,35,5,39,9,51,157,310,10,21,11,7,153,5,3,0,2,43,2,1,4,0,3,22,11,22,10,30,66,18,2,1,11,21,11,25,71,55,7,1,65,0,16,3,2,2,2,28,43,28,4,28,36,7,2,27,28,53,11,21,11,18,14,17,111,72,56,50,14,50,14,35,349,41,7,1,79,28,11,0,9,21,107,20,28,22,13,52,76,44,33,24,27,35,30,0,3,0,9,34,4,0,13,47,15,3,22,0,2,0,36,17,2,24,85,6,2,0,2,3,2,14,2,9,8,46,39,7,3,1,3,21,2,6,2,1,2,4,4,0,19,0,13,4,159,52,19,3,21,2,31,47,21,1,2,0,185,46,42,3,37,47,21,0,60,42,14,0,72,26,230,43,117,63,32,7,3,0,3,7,2,1,2,23,16,0,2,0,95,7,3,38,17,0,2,0,29,0,11,39,8,0,22,0,12,45,20,0,35,56,264,8,2,36,18,0,50,29,113,6,2,1,2,37,22,0,26,5,2,1,2,31,15,0,328,18,190,0,80,921,103,110,18,195,2749,1070,4050,582,8634,568,8,30,114,29,19,47,17,3,32,20,6,18,689,63,129,74,6,0,67,12,65,1,2,0,29,6135,9,1237,43,8,8952,286,50,2,18,3,9,395,2309,106,6,12,4,8,8,9,5991,84,2,70,2,1,3,0,3,1,3,3,2,11,2,0,2,6,2,64,2,3,3,7,2,6,2,27,2,3,2,4,2,0,4,6,2,339,3,24,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,30,2,24,2,7,2357,44,11,6,17,0,370,43,1301,196,60,67,8,0,1205,3,2,26,2,1,2,0,3,0,2,9,2,3,2,0,2,0,7,0,5,0,2,0,2,0,2,2,2,1,2,0,3,0,2,0,2,0,2,0,2,0,2,1,2,0,3,3,2,6,2,3,2,3,2,0,2,9,2,16,6,2,2,4,2,16,4421,42717,35,4148,12,221,3,5761,15,7472,3104,541,1507,4938]
 948  
 949  // eslint-disable-next-line comma-spacing
 950  const astralIdentifierCodes = [509,0,227,0,150,4,294,9,1368,2,2,1,6,3,41,2,5,0,166,1,574,3,9,9,370,1,154,10,176,2,54,14,32,9,16,3,46,10,54,9,7,2,37,13,2,9,6,1,45,0,13,2,49,13,9,3,2,11,83,11,7,0,161,11,6,9,7,3,56,1,2,6,3,1,3,2,10,0,11,1,3,6,4,4,193,17,10,9,5,0,82,19,13,9,214,6,3,8,28,1,83,16,16,9,82,12,9,9,84,14,5,9,243,14,166,9,71,5,2,1,3,3,2,0,2,1,13,9,120,6,3,6,4,0,29,9,41,6,2,3,9,0,10,10,47,15,406,7,2,7,17,9,57,21,2,13,123,5,4,0,2,1,2,6,2,0,9,9,49,4,2,1,2,4,9,9,330,3,19306,9,135,4,60,6,26,9,1014,0,2,54,8,3,82,0,12,1,19628,1,5319,4,4,5,9,7,3,6,31,3,149,2,1418,49,513,54,5,49,9,0,15,0,23,4,2,14,1361,6,2,16,3,6,2,1,2,4,262,6,10,9,419,13,1495,6,110,6,6,9,4759,9,787719,239]
 951  
 952  // This has a complexity linear to the value of the code. The
 953  // assumption is that looking up astral identifier characters is
 954  // rare.
 955  function isInAstralSet(code, set) {
 956    let pos = 0x10000
 957    for (let i = 0; i < set.length; i += 2) {
 958      pos += set[i]
 959      if (pos > code) return false
 960      pos += set[i + 1]
 961      if (pos >= code) return true
 962    }
 963  }
 964  
 965  // Test whether a given character code starts an identifier.
 966  
 967  function isIdentifierStart(code, astral) {
 968    if (code < 65) return code === 36
 969    if (code < 91) return true
 970    if (code < 97) return code === 95
 971    if (code < 123) return true
 972    if (code <= 0xffff) return code >= 0xaa && nonASCIIidentifierStart.test(String.fromCharCode(code))
 973    if (astral === false) return false
 974    return isInAstralSet(code, astralIdentifierStartCodes)
 975  }
 976  
 977  // Test whether a given character is part of an identifier.
 978  
 979  function isIdentifierChar(code, astral) {
 980    if (code < 48) return code === 36
 981    if (code < 58) return true
 982    if (code < 65) return false
 983    if (code < 91) return true
 984    if (code < 97) return code === 95
 985    if (code < 123) return true
 986    if (code <= 0xffff) return code >= 0xaa && nonASCIIidentifier.test(String.fromCharCode(code))
 987    if (astral === false) return false
 988    return isInAstralSet(code, astralIdentifierStartCodes) || isInAstralSet(code, astralIdentifierCodes)
 989  }
 990  
 991  function identifier () {
 992    let ch = source.codePointAt(pos);
 993    if (!isIdentifierStart(ch, true) || ch === '\\')
 994      return false;
 995    pos += codePointLen(ch);
 996    while (ch = source.codePointAt(pos)) {
 997      if (isIdentifierChar(ch, true)) {
 998        pos += codePointLen(ch);
 999      }
1000      else if (ch === '\\') {
1001        // no identifier escapes support for now
1002        return false;
1003      }
1004      else {
1005        break;
1006      }
1007    }
1008    return true;
1009  }
1010  
1011  function codePointLen (ch) {
1012    if (ch < 0x10000) return 1;
1013    return 2;
1014  }
1015  
1016  function codePointAtLast (bPos) {
1017    // Gives the UTF char for backtracking surrogates
1018    const ch = source.charCodeAt(bPos);
1019    if ((ch & 0xFC00) === 0xDC00)
1020      return (((source.charCodeAt(bPos - 1) & 0x3FF) << 10) | (ch & 0x3FF)) + 0x10000;
1021    return ch;
1022  }
1023  
1024  function throwIfImportStatement () {
1025    const startPos = pos;
1026    pos += 6;
1027    const ch = commentWhitespace();
1028    switch (ch) {
1029      // dynamic import
1030      case 40/*(*/:
1031        openTokenPosStack[openTokenDepth++] = startPos;
1032        return;
1033      // import.meta
1034      case 46/*.*/:
1035        throw new Error('Unexpected import.meta in CJS module.');
1036        return;
1037  
1038      default:
1039        // no space after "import" -> not an import keyword
1040        if (pos === startPos + 6)
1041          break;
1042      case 34/*"*/:
1043      case 39/*'*/:
1044      case 123/*{*/:
1045      case 42/***/:
1046        // import statement only permitted at base-level
1047        if (openTokenDepth !== 0) {
1048          pos--;
1049          return;
1050        }
1051        // import statements are a syntax error in CommonJS
1052        throw new Error('Unexpected import statement in CJS module.');
1053    }
1054  }
1055  
1056  function throwIfExportStatement () {
1057    pos += 6;
1058    const curPos = pos;
1059    const ch = commentWhitespace();
1060    if (pos === curPos && !isPunctuator(ch))
1061      return;
1062    throw new Error('Unexpected export statement in CJS module.');
1063  }
1064  
1065  function commentWhitespace () {
1066    let ch;
1067    do {
1068      ch = source.charCodeAt(pos);
1069      if (ch === 47/*/*/) {
1070        const next_ch = source.charCodeAt(pos + 1);
1071        if (next_ch === 47/*/*/)
1072          lineComment();
1073        else if (next_ch === 42/***/)
1074          blockComment();
1075        else
1076          return ch;
1077      }
1078      else if (!isBrOrWs(ch)) {
1079        return ch;
1080      }
1081    } while (pos++ < end);
1082    return ch;
1083  }
1084  
1085  function templateString () {
1086    while (pos++ < end) {
1087      const ch = source.charCodeAt(pos);
1088      if (ch === 36/*$*/ && source.charCodeAt(pos + 1) === 123/*{*/) {
1089        pos++;
1090        templateStack[templateStackDepth++] = templateDepth;
1091        templateDepth = ++openTokenDepth;
1092        return;
1093      }
1094      if (ch === 96/*`*/)
1095        return;
1096      if (ch === 92/*\*/)
1097        pos++;
1098    }
1099    syntaxError();
1100  }
1101  
1102  function blockComment () {
1103    pos++;
1104    while (pos++ < end) {
1105      const ch = source.charCodeAt(pos);
1106      if (ch === 42/***/ && source.charCodeAt(pos + 1) === 47/*/*/) {
1107        pos++;
1108        return;
1109      }
1110    }
1111  }
1112  
1113  function lineComment () {
1114    while (pos++ < end) {
1115      const ch = source.charCodeAt(pos);
1116      if (ch === 10/*\n*/ || ch === 13/*\r*/)
1117        return;
1118    }
1119  }
1120  
1121  function singleQuoteString () {
1122    while (pos++ < end) {
1123      let ch = source.charCodeAt(pos);
1124      if (ch === 39/*'*/)
1125        return;
1126      if (ch === 92/*\*/) {
1127        ch = source.charCodeAt(++pos);
1128        if (ch === 13/*\r*/ && source.charCodeAt(pos + 1) === 10/*\n*/)
1129          pos++;
1130      }
1131      else if (isBr(ch))
1132        break;
1133    }
1134    throw new Error('Unterminated string.');
1135  }
1136  
1137  function doubleQuoteString () {
1138    while (pos++ < end) {
1139      let ch = source.charCodeAt(pos);
1140      if (ch === 34/*"*/)
1141        return;
1142      if (ch === 92/*\*/) {
1143        ch = source.charCodeAt(++pos);
1144        if (ch === 13/*\r*/ && source.charCodeAt(pos + 1) === 10/*\n*/)
1145          pos++;
1146      }
1147      else if (isBr(ch))
1148        break;
1149    }
1150    throw new Error('Unterminated string.');
1151  }
1152  
1153  function regexCharacterClass () {
1154    while (pos++ < end) {
1155      let ch = source.charCodeAt(pos);
1156      if (ch === 93/*]*/)
1157        return ch;
1158      if (ch === 92/*\*/)
1159        pos++;
1160      else if (ch === 10/*\n*/ || ch === 13/*\r*/)
1161        break;
1162    }
1163    throw new Error('Syntax error reading regular expression class.');
1164  }
1165  
1166  function regularExpression () {
1167    while (pos++ < end) {
1168      let ch = source.charCodeAt(pos);
1169      if (ch === 47/*/*/)
1170        return;
1171      if (ch === 91/*[*/)
1172        ch = regexCharacterClass();
1173      else if (ch === 92/*\*/)
1174        pos++;
1175      else if (ch === 10/*\n*/ || ch === 13/*\r*/)
1176        break;
1177    }
1178    throw new Error('Syntax error reading regular expression.');
1179  }
1180  
1181  // Note: non-asii BR and whitespace checks omitted for perf / footprint
1182  // if there is a significant user need this can be reconsidered
1183  function isBr (c) {
1184    return c === 13/*\r*/ || c === 10/*\n*/;
1185  }
1186  
1187  function isBrOrWs (c) {
1188    return c > 8 && c < 14 || c === 32 || c === 160;
1189  }
1190  
1191  function isBrOrWsOrPunctuatorNotDot (c) {
1192    return c > 8 && c < 14 || c === 32 || c === 160 || isPunctuator(c) && c !== 46/*.*/;
1193  }
1194  
1195  function keywordStart (pos) {
1196    return pos === 0 || isBrOrWsOrPunctuatorNotDot(source.charCodeAt(pos - 1));
1197  }
1198  
1199  function readPrecedingKeyword (pos, match) {
1200    if (pos < match.length - 1)
1201      return false;
1202    return source.startsWith(match, pos - match.length + 1) && (pos === 0 || isBrOrWsOrPunctuatorNotDot(source.charCodeAt(pos - match.length)));
1203  }
1204  
1205  function readPrecedingKeyword1 (pos, ch) {
1206    return source.charCodeAt(pos) === ch && (pos === 0 || isBrOrWsOrPunctuatorNotDot(source.charCodeAt(pos - 1)));
1207  }
1208  
1209  // Detects one of case, debugger, delete, do, else, in, instanceof, new,
1210  //   return, throw, typeof, void, yield, await
1211  function isExpressionKeyword (pos) {
1212    switch (source.charCodeAt(pos)) {
1213      case 100/*d*/:
1214        switch (source.charCodeAt(pos - 1)) {
1215          case 105/*i*/:
1216            // void
1217            return readPrecedingKeyword(pos - 2, 'vo');
1218          case 108/*l*/:
1219            // yield
1220            return readPrecedingKeyword(pos - 2, 'yie');
1221          default:
1222            return false;
1223        }
1224      case 101/*e*/:
1225        switch (source.charCodeAt(pos - 1)) {
1226          case 115/*s*/:
1227            switch (source.charCodeAt(pos - 2)) {
1228              case 108/*l*/:
1229                // else
1230                return readPrecedingKeyword1(pos - 3, 101/*e*/);
1231              case 97/*a*/:
1232                // case
1233                return readPrecedingKeyword1(pos - 3, 99/*c*/);
1234              default:
1235                return false;
1236            }
1237          case 116/*t*/:
1238            // delete
1239            return readPrecedingKeyword(pos - 2, 'dele');
1240          default:
1241            return false;
1242        }
1243      case 102/*f*/:
1244        if (source.charCodeAt(pos - 1) !== 111/*o*/ || source.charCodeAt(pos - 2) !== 101/*e*/)
1245          return false;
1246        switch (source.charCodeAt(pos - 3)) {
1247          case 99/*c*/:
1248            // instanceof
1249            return readPrecedingKeyword(pos - 4, 'instan');
1250          case 112/*p*/:
1251            // typeof
1252            return readPrecedingKeyword(pos - 4, 'ty');
1253          default:
1254            return false;
1255        }
1256      case 110/*n*/:
1257        // in, return
1258        return readPrecedingKeyword1(pos - 1, 105/*i*/) || readPrecedingKeyword(pos - 1, 'retur');
1259      case 111/*o*/:
1260        // do
1261        return readPrecedingKeyword1(pos - 1, 100/*d*/);
1262      case 114/*r*/:
1263        // debugger
1264        return readPrecedingKeyword(pos - 1, 'debugge');
1265      case 116/*t*/:
1266        // await
1267        return readPrecedingKeyword(pos - 1, 'awai');
1268      case 119/*w*/:
1269        switch (source.charCodeAt(pos - 1)) {
1270          case 101/*e*/:
1271            // new
1272            return readPrecedingKeyword1(pos - 2, 110/*n*/);
1273          case 111/*o*/:
1274            // throw
1275            return readPrecedingKeyword(pos - 2, 'thr');
1276          default:
1277            return false;
1278        }
1279    }
1280    return false;
1281  }
1282  
1283  function isParenKeyword (curPos) {
1284    return source.charCodeAt(curPos) === 101/*e*/ && source.startsWith('whil', curPos - 4) ||
1285        source.charCodeAt(curPos) === 114/*r*/ && source.startsWith('fo', curPos - 2) ||
1286        source.charCodeAt(curPos - 1) === 105/*i*/ && source.charCodeAt(curPos) === 102/*f*/;
1287  }
1288  
1289  function isPunctuator (ch) {
1290    // 23 possible punctuator endings: !%&()*+,-./:;<=>?[]^{}|~
1291    return ch === 33/*!*/ || ch === 37/*%*/ || ch === 38/*&*/ ||
1292      ch > 39 && ch < 48 || ch > 57 && ch < 64 ||
1293      ch === 91/*[*/ || ch === 93/*]*/ || ch === 94/*^*/ ||
1294      ch > 122 && ch < 127;
1295  }
1296  
1297  function isExpressionPunctuator (ch) {
1298    // 20 possible expression endings: !%&(*+,-.:;<=>?[^{|~
1299    return ch === 33/*!*/ || ch === 37/*%*/ || ch === 38/*&*/ ||
1300      ch > 39 && ch < 47 && ch !== 41 || ch > 57 && ch < 64 ||
1301      ch === 91/*[*/ || ch === 94/*^*/ || ch > 122 && ch < 127 && ch !== 125/*}*/;
1302  }
1303  
1304  function isExpressionTerminator (curPos) {
1305    // detects:
1306    // => ; ) finally catch else
1307    // as all of these followed by a { will indicate a statement brace
1308    switch (source.charCodeAt(curPos)) {
1309      case 62/*>*/:
1310        return source.charCodeAt(curPos - 1) === 61/*=*/;
1311      case 59/*;*/:
1312      case 41/*)*/:
1313        return true;
1314      case 104/*h*/:
1315        return source.startsWith('catc', curPos - 4);
1316      case 121/*y*/:
1317        return source.startsWith('finall', curPos - 6);
1318      case 101/*e*/:
1319        return source.startsWith('els', curPos - 3);
1320    }
1321    return false;
1322  }
1323  
1324  const initPromise = Promise.resolve();
1325  
1326  module.exports.init = () => initPromise;
1327  module.exports.parse = parseCJS;