SQLite

      [
        'bigIntEnabled'
      ].forEach(function(k){
        if(Object.getOwnPropertyDescriptor(src, k)) rc[k] = src[k];
      });
      rc.version = sqlite3.version;
      rc.vfsList = sqlite3.capi.sqlite3_js_vfs_list();

      return rc;
    },

    /**
       Exports the database to a byte array, as per
       sqlite3_serialize(). Response is an object:

      };
      wState.xfer.push(response.byteArray.buffer);
      return response;
    }/*export()*/,

    toss: function(ev){
      toss("Testing worker exception");






    }
  }/*wMsgHandler*/;

  globalThis.onmessage = async function(ev){
    ev = ev.data;
    let result, dbId = ev.dbId, evType = ev.type;
    const arrivalTime = performance.now();

   - The counterpart Worker (see below) could not be loaded.

   - The environment does not support OPFS. That includes when
     this function is called from the main window thread.

  Significant notes and limitations:





  - The OPFS features used here are only available in dedicated Worker
    threads. This file tries to detect that case, resulting in a
    rejected Promise if those features do not seem to be available.

  - It requires the SharedArrayBuffer and Atomics classes, and the
    former is only available if the HTTP server emits the so-called
    COOP and COEP response headers. These features are required for
    proxying OPFS's synchronous API via the synchronous interface
    required by the sqlite3_vfs API.

  - This function may only be called a single time. When called, this
    function removes itself from the sqlite3 object.

  All arguments to this function are for internal/development purposes
  only. They do not constitute a public API and may change at any
  time.

  The argument may optionally be a plain object with the following
  configuration options:

  - proxyUri: name of the async proxy JS file.

  - verbose (=2): an integer 0-3. 0 disables all logging, 1 enables
    logging of errors. 2 enables logging of warnings and errors. 3
    additionally enables debugging info. Logging is performed
    via the sqlite3.config.{log|warn|error}() functions.

  - sanityChecks (=false): if true, some basic sanity tests are run on
    the OPFS VFS API after it's initialized, before the returned
    Promise resolves. This is only intended for testing and
    development of the VFS, not client-side use.

  On success, the Promise resolves to the top-most sqlite3 namespace
  object and that object gets a new object installed in its
  `opfs` property, containing several OPFS-specific utilities.
*/
const installOpfsVfs = function callee(options){
  if(!globalThis.SharedArrayBuffer

      }catch(e){
        //sqlite3.config.warn("mkdir(",absDirName,") failed:",e);
        return false;
      }
    };
    /**
       Checks whether the given OPFS filesystem entry exists,
       returning true if it does, false if it doesn't or if an
       exception is intercepted while trying to make the
       determination.
    */
    opfsUtil.entryExists = async function(fsEntryName){
      try {
        const [dh, fn] = await opfsUtil.getDirForFilename(fsEntryName);
        await dh.getFileHandle(fn);
        return true;
      }catch(e){

          });
        }
        return false;
      }
    };

    /**
       Traverses the OPFS filesystem, calling a callback for each
       entry.  The argument may be either a callback function or an
       options object with any of the following properties:

       - `callback`: function which gets called for each filesystem
         entry.  It gets passed 3 arguments: 1) the
         FileSystemFileHandle or FileSystemDirectoryHandle of each
         entry (noting that both are instanceof FileSystemHandle). 2)
         the FileSystemDirectoryHandle of the parent directory. 3) the
         current depth level, with 0 being at the top of the tree

       If this function is passed a function, it is assumed to be the
       callback.

       Returns a promise because it has to (by virtue of being async)
       but that promise has no specific meaning: the traversal it
       performs is synchronous. The promise must be used to catch any
       exceptions propagated by the callback, however.





    */
    opfsUtil.traverse = async function(opt){
      const defaultOpt = {
        recursive: true,
        directory: opfsUtil.rootDirectory
      };
      if('function'===typeof opt){

  float rLimit;       /* Maximum NNN value for this transform */
  float rXform;       /* Constant used for this transform */
} aXformType[] = {
  /* 0 */ { 6, "second",   4.6427e+14,         1.0  },
  /* 1 */ { 6, "minute",   7.7379e+12,        60.0  },
  /* 2 */ { 4, "hour",     1.2897e+11,      3600.0  },
  /* 3 */ { 3, "day",      5373485.0,      86400.0  },
  /* 4 */ { 5, "month",    176546.0,     2592000.0  },
  /* 5 */ { 4, "year",     14713.0,     31536000.0  },
};

/*
** If the DateTime p is raw number, try to figure out if it is
** a julian day number of a unix timestamp.  Set the p value
** appropriately.
*/

  int y, z;
  char zBuf[100];
  UNUSED_PARAMETER(argc);
  assert( argc==3 );
  x = sqlite3_value_double(argv[0]);
  y = sqlite3_value_int(argv[1]);
  z = sqlite3_value_int(argv[2]);
  if( z<=0 ) z = 1;
  sqlite3FpDecode(&s, x, y, z);
  if( s.isSpecial==2 ){
    sqlite3_snprintf(sizeof(zBuf), zBuf, "NaN");
  }else{
    sqlite3_snprintf(sizeof(zBuf), zBuf, "%c%.*s/%d", s.sign, s.n, s.z, s.iDP);
  }
  sqlite3_result_text(context, zBuf, -1, SQLITE_TRANSIENT);

  memset(&data, 0, sizeof(data));
#ifdef SQLITE_DEBUG
  if( sqlite3_memory_used()>mem_main_enter ){
    eputf("Memory leaked: %u bytes\n",
          (unsigned int)(sqlite3_memory_used()-mem_main_enter));
  }
#endif
#else /* SQLITE_SHELL_FIDDLE... */
  shell_main_exit:
#endif
  return rc;
}


#ifdef SQLITE_SHELL_FIDDLE
/* Only for emcc experimentation purposes. */
int fiddle_experiment(int a,int b){

#define WHERE_GROUPBY          0x0040 /* pOrderBy is really a GROUP BY */
#define WHERE_DISTINCTBY       0x0080 /* pOrderby is really a DISTINCT clause */
#define WHERE_WANT_DISTINCT    0x0100 /* All output needs to be distinct */
#define WHERE_SORTBYGROUP      0x0200 /* Support sqlite3WhereIsSorted() */
#define WHERE_AGG_DISTINCT     0x0400 /* Query is "SELECT agg(DISTINCT ...)" */
#define WHERE_ORDERBY_LIMIT    0x0800 /* ORDERBY+LIMIT on the inner loop */
#define WHERE_RIGHT_JOIN       0x1000 /* Processing a RIGHT JOIN */
#define WHERE_KEEP_ALL_JOINS   0x2000 /* Do not do the omit-noop-join opt */
#define WHERE_USE_LIMIT        0x4000 /* Use the LIMIT in cost estimates */
                        /*     0x8000    not currently used */

/* Allowed return values from sqlite3WhereIsDistinct()
*/
#define WHERE_DISTINCT_NOOP      0  /* DISTINCT keyword not used */
#define WHERE_DISTINCT_UNIQUE    1  /* No duplicates */

  return x;
}

/*
** Decode a floating-point value into an approximate decimal
** representation.
**
** If iRound<=0 then round to -iRound significant digits to the
** the left of the decimal point, or to a maximum of mxRound total
** significant digits.

**
** If iRound>0 round to min(iRound,mxRound) significant digits total.
**
** mxRound must be positive.
**
** The significant digits of the decimal representation are
** stored in p->z[] which is a often (but not always) a pointer
** into the middle of p->zBuf[].  There are p->n significant digits.
** The p->z[] array is *not* zero-terminated.
*/
void sqlite3FpDecode(FpDecode *p, double r, int iRound, int mxRound){
  int i;
  u64 v;
  int e, exp = 0;
  p->isSpecial = 0;
  p->z = p->zBuf;

  assert( mxRound>0 );

  /* Convert negative numbers to positive.  Deal with Infinity, 0.0, and
  ** NaN. */
  if( r<0.0 ){
    p->sign = '-';
    r = -r;
  }else if( r==0.0 ){

**   5) The table must not have an inner-join ON or USING clause if there is
**      a RIGHT JOIN anywhere in the query.  Otherwise the ON/USING clause
**      might move from the right side to the left side of the RIGHT JOIN.
**      Note: Due to (2), this condition can only arise if the table is
**      the right-most table of a subquery that was flattened into the
**      main query and that subquery was the right-hand operand of an
**      inner join that held an ON or USING clause.
**   6) The ORDER BY clause has 63 or fewer terms
**   7) The omit-noop-join optimization is enabled.
**
** Items (1), (6), and (7) are checked by the caller.
**
** For example, given:
**
**     CREATE TABLE t1(ipk INTEGER PRIMARY KEY, v1);
**     CREATE TABLE t2(ipk INTEGER PRIMARY KEY, v2);
**     CREATE TABLE t3(ipk INTEGER PRIMARY KEY, v3);
**

  memset(&sWLB, 0, sizeof(sWLB));

  /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
  testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
  if( pOrderBy && pOrderBy->nExpr>=BMS ){
    pOrderBy = 0;
    wctrlFlags &= ~WHERE_WANT_DISTINCT;
    wctrlFlags |= WHERE_KEEP_ALL_JOINS; /* Disable omit-noop-join opt */
  }

  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask
  */
  testcase( pTabList->nSrc==BMS );
  if( pTabList->nSrc>BMS ){

  ** procedure to keep the sqlite3WhereBegin() procedure from becoming
  ** too large.  If sqlite3WhereBegin() becomes too large, that prevents
  ** some C-compiler optimizers from in-lining the
  ** sqlite3WhereCodeOneLoopStart() procedure, and it is important to
  ** in-line sqlite3WhereCodeOneLoopStart() for performance reasons.
  */
  notReady = ~(Bitmask)0;
  if( pWInfo->nLevel>=2       /* Must be a join, or this opt8n is pointless */
   && pResultSet!=0           /* Condition (1) */
   && 0==(wctrlFlags & (WHERE_AGG_DISTINCT|WHERE_KEEP_ALL_JOINS)) /* (1),(6) */
   && OptimizationEnabled(db, SQLITE_OmitNoopJoin)                /* (7) */
  ){
    notReady = whereOmitNoopJoin(pWInfo, notReady);
    nTabList = pWInfo->nLevel;
    assert( nTabList>0 );
  }

  /* Check to see if there are any SEARCH loops that might benefit from