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x/web_bson/src/parser/serializer.ts

web_bson is a fork from mongodb/js-bson
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import { Code } from "../code.ts";import {  BSON_BINARY_SUBTYPE_DEFAULT,  BSON_INT32_MAX,  BSON_INT32_MIN,  BSONData,} from "../constants.ts";import { DBRef, DBRefLike } from "../db_ref.ts";import { Decimal128 } from "../decimal128.ts";import { Double } from "../double.ts";import { BSONError, BSONTypeError } from "../error.ts";import { writeIEEE754 } from "../float_parser.ts";import { Int32 } from "../int_32.ts";import { Long } from "../long.ts";import { MaxKey, MinKey } from "../key.ts";import { ObjectId } from "../objectid.ts";import { Timestamp } from "../timestamp.ts";import { BSONRegExp } from "../regexp.ts";import { Encoding, normalizedFunctionString, writeToBytes } from "./utils.ts";import { Binary, BinarySizes, BSONSymbol, Document } from "../bson.ts";/** @public */export interface SerializeOptions {  /** the serializer will check if keys are valid. */  checkKeys?: boolean;  /** serialize the javascript functions **(default:false)**. */  serializeFunctions?: boolean;  /** serialize will not emit undefined fields **(default:true)** */  ignoreUndefined?: boolean;  /** the index in the buffer where we wish to start serializing into */  index?: number;}
// deno-lint-ignore no-control-regexconst regexp = /\x00/;const ignoreKeys = new Set(["$db", "$ref", "$id", "$clusterTime"]);
/* * isArray indicates if we are writing to a BSON array (type 0x04) * which forces the "key" which really an array index as a string to be written as ascii * This will catch any errors in index as a string generation */
function serializeString(  buffer: Uint8Array,  key: string,  value: string,  index: number,  isArray?: boolean,) {  // Encode String type  buffer[index++] = BSONData.STRING;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index = index + numberOfWrittenBytes + 1;  buffer[index - 1] = 0;  // Write the string  const size = writeToBytes(buffer, value, index + 4, Encoding.Utf8);  // Write the size of the string to buffer  buffer[index + 3] = ((size + 1) >> 24) & 0xff;  buffer[index + 2] = ((size + 1) >> 16) & 0xff;  buffer[index + 1] = ((size + 1) >> 8) & 0xff;  buffer[index] = (size + 1) & 0xff;  // Update index  index = index + 4 + size;  // Write zero  buffer[index++] = 0;  return index;}
function serializeNumber(  buffer: Uint8Array,  key: string,  value: number,  index: number,  isArray?: boolean,) {  // We have an integer value  // TODO(NODE-2529): Add support for big int  if (    Number.isInteger(value) &&    value >= BSON_INT32_MIN &&    value <= BSON_INT32_MAX  ) {    // If the value fits in 32 bits encode as int32    // Set int type 32 bits or less    buffer[index++] = BSONData.INT;    // Number of written bytes    const numberOfWrittenBytes = !isArray      ? writeToBytes(buffer, key, index, Encoding.Utf8)      : writeToBytes(buffer, key, index, Encoding.Ascii);    // Encode the name    index += numberOfWrittenBytes;    buffer[index++] = 0;    // Write the int value    buffer[index++] = value & 0xff;    buffer[index++] = (value >> 8) & 0xff;    buffer[index++] = (value >> 16) & 0xff;    buffer[index++] = (value >> 24) & 0xff;  } else {    // Encode as double    buffer[index++] = BSONData.NUMBER;    // Number of written bytes    const numberOfWrittenBytes = !isArray      ? writeToBytes(buffer, key, index, Encoding.Utf8)      : writeToBytes(buffer, key, index, Encoding.Ascii);    // Encode the name    index += numberOfWrittenBytes;    buffer[index++] = 0;    // Write float    writeIEEE754(buffer, value, index, "little", 52, 8);    // Adjust index    index += 8;  }
  return index;}
function serializeNull(  buffer: Uint8Array,  key: string,  _: unknown,  index: number,  isArray?: boolean,) {  // Set long type  buffer[index++] = BSONData.NULL;
  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);
  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  return index;}
function serializeBoolean(  buffer: Uint8Array,  key: string,  value: boolean,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.BOOLEAN;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Encode the boolean value  buffer[index++] = value ? 1 : 0;  return index;}
function serializeDate(  buffer: Uint8Array,  key: string,  value: Date,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.DATE;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;
  // Write the date  const dateInMilis = Long.fromNumber(value.getTime());  const lowBits = dateInMilis.getLowBits();  const highBits = dateInMilis.getHighBits();  // Encode low bits  buffer[index++] = lowBits & 0xff;  buffer[index++] = (lowBits >> 8) & 0xff;  buffer[index++] = (lowBits >> 16) & 0xff;  buffer[index++] = (lowBits >> 24) & 0xff;  // Encode high bits  buffer[index++] = highBits & 0xff;  buffer[index++] = (highBits >> 8) & 0xff;  buffer[index++] = (highBits >> 16) & 0xff;  buffer[index++] = (highBits >> 24) & 0xff;  return index;}
function serializeRegExp(  buffer: Uint8Array,  key: string,  value: RegExp,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.REGEXP;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);
  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  if (value.source && value.source.match(regexp) != null) {    throw Error(`value ${value.source} must not contain null bytes`);  }  // Adjust the index  index += writeToBytes(buffer, value.source, index, Encoding.Utf8);  // Write zero  buffer[index++] = 0x00;  // Write the parameters  if (value.ignoreCase) buffer[index++] = 0x69; // i  if (value.global) buffer[index++] = 0x73; // s  if (value.multiline) buffer[index++] = 0x6d; // m
  // Add ending zero  buffer[index++] = 0x00;  return index;}
function serializeBSONRegExp(  buffer: Uint8Array,  key: string,  value: BSONRegExp,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.REGEXP;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;
  // Check the pattern for 0 bytes  if (value.pattern.match(regexp) != null) {    // The BSON spec doesn't allow keys with null bytes because keys are    // null-terminated.    throw Error(`pattern ${value.pattern} must not contain null bytes`);  }
  // Adjust the index  index += writeToBytes(buffer, value.pattern, index, Encoding.Utf8);  // Write zero  buffer[index++] = 0x00;  // Write the options  index += writeToBytes(    buffer,    value.options.split("").sort().join(""),    index,    Encoding.Utf8,  );  // Add ending zero  buffer[index++] = 0x00;  return index;}
function serializeMinMax(  buffer: Uint8Array,  key: string,  value: MinKey | MaxKey,  index: number,  isArray?: boolean,) {  // Write the type of either min or max key  if (value === null) {    buffer[index++] = BSONData.NULL;  } else if (value instanceof MinKey) {    buffer[index++] = BSONData.MIN_KEY;  } else {    buffer[index++] = BSONData.MAX_KEY;  }
  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  return index;}
function serializeObjectId(  buffer: Uint8Array,  key: string,  value: ObjectId,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.OID;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);
  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;
  // Write the objectId into the shared buffer  if (typeof value.id === "string") {    writeToBytes(buffer, value.id, index, Encoding.Ascii);  } else if (value.id instanceof Uint8Array) {    // Use the standard JS methods here because buffer.copy() is buggy with the    // browser polyfill    buffer.set(value.id.subarray(0, 12), index);  } else {    throw new BSONTypeError(      `object [${JSON.stringify(value)}] is not a valid ObjectId`,    );  }
  // Adjust index  return index + 12;}
function serializeBuffer(  buffer: Uint8Array,  key: string,  value: Uint8Array,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.BINARY;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Get size of the buffer (current write point)  const size = value.length;  // Write the size of the string to buffer  buffer[index++] = size & 0xff;  buffer[index++] = (size >> 8) & 0xff;  buffer[index++] = (size >> 16) & 0xff;  buffer[index++] = (size >> 24) & 0xff;  // Write the default subtype  buffer[index++] = BSON_BINARY_SUBTYPE_DEFAULT;  // Copy the content form the binary field to the buffer  buffer.set(value, index);  // Adjust the index  index += size;  return index;}
function serializeObject(  buffer: Uint8Array,  key: string,  value: Document,  index: number,  checkKeys = false,  depth = 0,  serializeFunctions = false,  ignoreUndefined = true,  isArray = false,  path: Document[] = [],) {  for (let i = 0; i < path.length; i++) {    if (path[i] === value) throw new BSONError("cyclic dependency detected");  }
  // Push value to stack  path.push(value);  // Write the type  buffer[index++] = Array.isArray(value) ? BSONData.ARRAY : BSONData.OBJECT;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  const endIndex = serializeInto(    buffer,    value,    checkKeys,    index,    depth + 1,    serializeFunctions,    ignoreUndefined,    path,  );  // Pop stack  path.pop();  return endIndex;}
function serializeDecimal128(  buffer: Uint8Array,  key: string,  value: Decimal128,  index: number,  isArray?: boolean,) {  buffer[index++] = BSONData.DECIMAL128;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Write the data from the value  // Prefer the standard JS methods because their typechecking is not buggy,  // unlike the `buffer` polyfill's.  buffer.set(value.bytes.subarray(0, 16), index);  return index + 16;}
function serializeLong(  buffer: Uint8Array,  key: string,  value: Long,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = value instanceof Timestamp    ? BSONData.TIMESTAMP    : BSONData.LONG;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Write the date  const lowBits = value.getLowBits();  const highBits = value.getHighBits();  // Encode low bits  buffer[index++] = lowBits & 0xff;  buffer[index++] = (lowBits >> 8) & 0xff;  buffer[index++] = (lowBits >> 16) & 0xff;  buffer[index++] = (lowBits >> 24) & 0xff;  // Encode high bits  buffer[index++] = highBits & 0xff;  buffer[index++] = (highBits >> 8) & 0xff;  buffer[index++] = (highBits >> 16) & 0xff;  buffer[index++] = (highBits >> 24) & 0xff;  return index;}
function serializeInt32(  buffer: Uint8Array,  key: string,  value: Int32 | number,  index: number,  isArray?: boolean,) {  value = value.valueOf();  // Set int type 32 bits or less  buffer[index++] = BSONData.INT;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Write the int value  buffer[index++] = value & 0xff;  buffer[index++] = (value >> 8) & 0xff;  buffer[index++] = (value >> 16) & 0xff;  buffer[index++] = (value >> 24) & 0xff;  return index;}
function serializeDouble(  buffer: Uint8Array,  key: string,  value: Double,  index: number,  isArray?: boolean,) {  // Encode as double  buffer[index++] = BSONData.NUMBER;
  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);
  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;
  // Write float  writeIEEE754(buffer, value.value, index, "little", 52, 8);
  // Adjust index  index += 8;  return index;}
function serializeFunction(  buffer: Uint8Array,  key: string,  // deno-lint-ignore ban-types  value: Function,  index: number,  _checkKeys = false,  _depth = 0,  isArray?: boolean,) {  buffer[index++] = BSONData.CODE;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Function string  const functionString = normalizedFunctionString(value);
  // Write the string  const size = writeToBytes(buffer, functionString, index + 4, Encoding.Utf8) +    1;  // Write the size of the string to buffer  buffer[index] = size & 0xff;  buffer[index + 1] = (size >> 8) & 0xff;  buffer[index + 2] = (size >> 16) & 0xff;  buffer[index + 3] = (size >> 24) & 0xff;  // Update index  index = index + 4 + size - 1;  // Write zero  buffer[index++] = 0;  return index;}
function serializeCode(  buffer: Uint8Array,  key: string,  value: Code,  index: number,  checkKeys = false,  depth = 0,  serializeFunctions = false,  ignoreUndefined = true,  isArray = false,) {  if (value.scope && typeof value.scope === "object") {    // Write the type    buffer[index++] = BSONData.CODE_W_SCOPE;    // Number of written bytes    const numberOfWrittenBytes = !isArray      ? writeToBytes(buffer, key, index, Encoding.Utf8)      : writeToBytes(buffer, key, index, Encoding.Ascii);    // Encode the name    index += numberOfWrittenBytes;    buffer[index++] = 0;
    // Starting index    let startIndex = index;
    // Serialize the function    // Get the function string    const functionString = typeof value.code === "string"      ? value.code      : value.code.toString();    // Index adjustment    index += 4;    // Write string into buffer    const codeSize =      writeToBytes(buffer, functionString, index + 4, Encoding.Utf8) +      1;    // Write the size of the string to buffer    buffer[index] = codeSize & 0xff;    buffer[index + 1] = (codeSize >> 8) & 0xff;    buffer[index + 2] = (codeSize >> 16) & 0xff;    buffer[index + 3] = (codeSize >> 24) & 0xff;    // Write end 0    buffer[index + 4 + codeSize - 1] = 0;    // Write the    index = index + codeSize + 4;
    //    // Serialize the scope value    const endIndex = serializeInto(      buffer,      value.scope,      checkKeys,      index,      depth + 1,      serializeFunctions,      ignoreUndefined,    );    index = endIndex - 1;
    // Writ the total    const totalSize = endIndex - startIndex;
    // Write the total size of the object    buffer[startIndex++] = totalSize & 0xff;    buffer[startIndex++] = (totalSize >> 8) & 0xff;    buffer[startIndex++] = (totalSize >> 16) & 0xff;    buffer[startIndex++] = (totalSize >> 24) & 0xff;  } else {    buffer[index++] = BSONData.CODE;    // Number of written bytes    const numberOfWrittenBytes = !isArray      ? writeToBytes(buffer, key, index, Encoding.Utf8)      : writeToBytes(buffer, key, index, Encoding.Ascii);    // Encode the name    index += numberOfWrittenBytes;    buffer[index++] = 0;    // Function string    const functionString = value.code.toString();    // Write the string    const size =      writeToBytes(buffer, functionString, index + 4, Encoding.Utf8) + 1;    // Write the size of the string to buffer    buffer[index] = size & 0xff;    buffer[index + 1] = (size >> 8) & 0xff;    buffer[index + 2] = (size >> 16) & 0xff;    buffer[index + 3] = (size >> 24) & 0xff;    // Update index    index = index + 4 + size - 1;  }  // Write zero  buffer[index++] = 0;
  return index;}
function serializeBinary(  buffer: Uint8Array,  key: string,  value: Binary,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.BINARY;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Extract the buffer  const data = value.buffer;  // Calculate size  let size = value.buffer.length;  // Add the deprecated 02 type 4 bytes of size to total  if (value.subType === BinarySizes.SUBTYPE_BYTE_ARRAY) size += 4;  // Write the size of the string to buffer  buffer[index++] = size & 0xff;  buffer[index++] = (size >> 8) & 0xff;  buffer[index++] = (size >> 16) & 0xff;  buffer[index++] = (size >> 24) & 0xff;  // Write the subtype to the buffer  buffer[index++] = value.subType;
  // If we have binary type 2 the 4 first bytes are the size  if (value.subType === BinarySizes.SUBTYPE_BYTE_ARRAY) {    size -= 4;    buffer[index++] = size & 0xff;    buffer[index++] = (size >> 8) & 0xff;    buffer[index++] = (size >> 16) & 0xff;    buffer[index++] = (size >> 24) & 0xff;  }
  // Write the data to the object  buffer.set(data, index);  // Adjust the index  index += size;  return index;}
function serializeSymbol(  buffer: Uint8Array,  key: string,  value: BSONSymbol,  index: number,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.SYMBOL;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;  // Write the string  const size = writeToBytes(buffer, value.value, index + 4, Encoding.Utf8) + 1;  // Write the size of the string to buffer  buffer[index] = size & 0xff;  buffer[index + 1] = (size >> 8) & 0xff;  buffer[index + 2] = (size >> 16) & 0xff;  buffer[index + 3] = (size >> 24) & 0xff;  // Update index  index = index + 4 + size - 1;  // Write zero  buffer[index++] = 0x00;  return index;}
function serializeDBRef(  buffer: Uint8Array,  key: string,  value: DBRef,  index: number,  depth: number,  serializeFunctions: boolean,  isArray?: boolean,) {  // Write the type  buffer[index++] = BSONData.OBJECT;  // Number of written bytes  const numberOfWrittenBytes = !isArray    ? writeToBytes(buffer, key, index, Encoding.Utf8)    : writeToBytes(buffer, key, index, Encoding.Ascii);
  // Encode the name  index += numberOfWrittenBytes;  buffer[index++] = 0;
  let startIndex = index;  let output: DBRefLike = {    $ref: value.collection,    $id: value.oid,  };
  if (value.db != null) {    output.$db = value.db;  }
  output = Object.assign(output, value.fields);  const endIndex = serializeInto(    buffer,    output,    false,    index,    depth + 1,    serializeFunctions,  );
  // Calculate object size  const size = endIndex - startIndex;  // Write the size  buffer[startIndex++] = size & 0xff;  buffer[startIndex++] = (size >> 8) & 0xff;  buffer[startIndex++] = (size >> 16) & 0xff;  buffer[startIndex++] = (size >> 24) & 0xff;  // Set index  return endIndex;}
export function serializeInto(  buffer: Uint8Array,  object: Document,  checkKeys = false,  startingIndex = 0,  depth = 0,  serializeFunctions = false,  ignoreUndefined = true,  path: Document[] = [],): number {  startingIndex = startingIndex || 0;  path = path || [];
  // Push the object to the path  path.push(object);
  // Start place to serialize into  let index = startingIndex + 4;
  // Special case isArray  if (Array.isArray(object)) {    // Get object keys    for (let i = 0; i < object.length; i++) {      const key = i.toString();      let value = object[i];
      // Is there an override value      if (value?.toBSON) {        if (typeof value.toBSON !== "function") {          throw new BSONTypeError("toBSON is not a function");        }        value = value.toBSON();      }
      if (typeof value === "string") {        index = serializeString(buffer, key, value, index, true);      } else if (typeof value === "number") {        index = serializeNumber(buffer, key, value, index, true);      } else if (typeof value === "bigint") {        throw new BSONTypeError(          "Unsupported type BigInt, please use Decimal128",        );      } else if (typeof value === "boolean") {        index = serializeBoolean(buffer, key, value, index, true);      } else if (value instanceof Date) {        index = serializeDate(buffer, key, value, index, true);      } else if (value === undefined) {        index = serializeNull(buffer, key, value, index, true);      } else if (value === null) {        index = serializeNull(buffer, key, value, index, true);      } else if (value instanceof ObjectId) {        index = serializeObjectId(buffer, key, value, index, true);      } else if (value instanceof Uint8Array) {        index = serializeBuffer(buffer, key, value, index, true);      } else if (value instanceof RegExp) {        index = serializeRegExp(buffer, key, value, index, true);      } else if (value instanceof Decimal128) {        index = serializeDecimal128(buffer, key, value, index, true);      } else if (value instanceof Long || value instanceof Timestamp) {        index = serializeLong(buffer, key, value, index, true);      } else if (value instanceof Double) {        index = serializeDouble(buffer, key, value, index, true);      } else if (typeof value === "function" && serializeFunctions) {        index = serializeFunction(          buffer,          key,          value,          index,          checkKeys,          depth,          true,        );      } else if (value instanceof Code) {        index = serializeCode(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,          ignoreUndefined,          true,        );      } else if (value instanceof Binary) {        index = serializeBinary(buffer, key, value, index, true);      } else if (value instanceof BSONSymbol) {        index = serializeSymbol(buffer, key, value, index, true);      } else if (value instanceof DBRef) {        index = serializeDBRef(          buffer,          key,          value,          index,          depth,          serializeFunctions,          true,        );      } else if (value instanceof BSONRegExp) {        index = serializeBSONRegExp(buffer, key, value, index, true);      } else if (value instanceof Int32) {        index = serializeInt32(buffer, key, value, index, true);      } else if (value instanceof MinKey || value instanceof MaxKey) {        index = serializeMinMax(buffer, key, value, index, true);      } else if (value instanceof Object) {        index = serializeObject(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,          ignoreUndefined,          true,          path,        );      } else {        throw new BSONTypeError(`Unrecognized or invalid BSON Type: ${value}`);      }    }  } else if (object instanceof Map) {    const iterator = object.entries();    let done = false;
    while (!done) {      // Unpack the next entry      const entry = iterator.next();      done = !!entry.done;      // Are we done, then skip and terminate      if (done) continue;
      // Get the entry values      const key = entry.value[0];      const value = entry.value[1];
      // Check the type of the value      const type = typeof value;
      // Check the key and throw error if it's illegal      if (typeof key === "string" && !ignoreKeys.has(key)) {        if (key.match(regexp) != null) {          // The BSON spec doesn't allow keys with null bytes because keys are          // null-terminated.          throw Error(`key ${key} must not contain null bytes`);        }
        if (checkKeys) {          if (key.startsWith("$")) {            throw Error(`key ${key} must not start with '$'`);          } else if (~key.indexOf(".")) {            throw Error(`key ${key} must not contain '.'`);          }        }      }
      if (type === "string") {        index = serializeString(buffer, key, value, index);      } else if (type === "number") {        index = serializeNumber(buffer, key, value, index);      } else if (        type === "bigint" || value instanceof BigInt64Array ||        value instanceof BigUint64Array      ) {        throw new BSONTypeError(          "Unsupported type BigInt, please use Decimal128",        );      } else if (type === "boolean") {        index = serializeBoolean(buffer, key, value, index);      } else if (value instanceof Date) {        index = serializeDate(buffer, key, value, index);      } else if (        value === null || (value === undefined && ignoreUndefined === false)      ) {        index = serializeNull(buffer, key, value, index);      } else if (value instanceof ObjectId) {        index = serializeObjectId(buffer, key, value, index);      } else if (value instanceof Uint8Array) {        index = serializeBuffer(buffer, key, value, index);      } else if (value instanceof RegExp) {        index = serializeRegExp(buffer, key, value, index);      } else if (type === "object" && value instanceof Object) {        index = serializeObject(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,          ignoreUndefined,          false,          path,        );      } else if (type === "object" && value instanceof Decimal128) {        index = serializeDecimal128(buffer, key, value, index);      } else if (value instanceof Long) {        index = serializeLong(buffer, key, value, index);      } else if (value instanceof Double) {        index = serializeDouble(buffer, key, value, index);      } else if (value instanceof Code) {        index = serializeCode(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,          ignoreUndefined,        );      } else if (typeof value === "function" && serializeFunctions) {        index = serializeFunction(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,        );      } else if (value instanceof Binary) {        index = serializeBinary(buffer, key, value, index);      } else if (value instanceof BSONSymbol) {        index = serializeSymbol(buffer, key, value, index);      } else if (value instanceof DBRef) {        index = serializeDBRef(          buffer,          key,          value,          index,          depth,          serializeFunctions,        );      } else if (value instanceof BSONRegExp) {        index = serializeBSONRegExp(buffer, key, value, index);      } else if (value instanceof Int32) {        index = serializeInt32(buffer, key, value, index);      } else if (value instanceof MinKey || value instanceof MaxKey) {        index = serializeMinMax(buffer, key, value, index);      } else {        throw new BSONTypeError(`Unrecognized or invalid BSON TYPE: ${value}`);      }    }  } else {    // Did we provide a custom serialization method    if (object.toBSON) {      if (typeof object.toBSON !== "function") {        throw new BSONTypeError("toBSON is not a function");      }      object = object.toBSON();      if (object != null && typeof object !== "object") {        throw new BSONTypeError("toBSON function did not return an object");      }    }
    // Iterate over all the keys    for (const key in object) {      let value = object[key];      // Is there an override value      if (value?.toBSON) {        if (typeof value.toBSON !== "function") {          throw new BSONTypeError("toBSON is not a function");        }        value = value.toBSON();      }
      // Check the type of the value      const type = typeof value;
      // Check the key and throw error if it's illegal      if (typeof key === "string" && !ignoreKeys.has(key)) {        if (key.match(regexp) != null) {          // The BSON spec doesn't allow keys with null bytes because keys are          // null-terminated.          throw Error(`key ${key} must not contain null bytes`);        }
        if (checkKeys) {          if (key.startsWith("$")) {            throw Error(`key ${key} must not start with '$'`);          } else if (~key.indexOf(".")) {            throw Error(`key ${key} must not contain '.'`);          }        }      }
      if (type === "string") {        index = serializeString(buffer, key, value, index);      } else if (type === "number") {        index = serializeNumber(buffer, key, value, index);      } else if (type === "bigint") {        throw new BSONTypeError(          "Unsupported type BigInt, please use Decimal128",        );      } else if (type === "boolean") {        index = serializeBoolean(buffer, key, value, index);      } else if (value instanceof Date) {        index = serializeDate(buffer, key, value, index);      } else if (value === undefined) {        if (ignoreUndefined === false) {          index = serializeNull(buffer, key, value, index);        }      } else if (value === null) {        index = serializeNull(buffer, key, value, index);      } else if (value instanceof ObjectId) {        index = serializeObjectId(buffer, key, value, index);      } else if (value instanceof Uint8Array) {        index = serializeBuffer(buffer, key, value, index);      } else if (value instanceof RegExp) {        index = serializeRegExp(buffer, key, value, index);      } else if (type === "object" && value instanceof Decimal128) {        index = serializeDecimal128(buffer, key, value, index);      } else if (value instanceof Long || value instanceof Timestamp) {        index = serializeLong(buffer, key, value, index);      } else if (value instanceof Double) {        index = serializeDouble(buffer, key, value, index);      } else if (value instanceof Code) {        index = serializeCode(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,          ignoreUndefined,        );      } else if (typeof value === "function" && serializeFunctions) {        index = serializeFunction(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,        );      } else if (value instanceof Binary) {        index = serializeBinary(buffer, key, value, index);      } else if (value instanceof BSONSymbol) {        index = serializeSymbol(buffer, key, value, index);      } else if (value instanceof DBRef) {        index = serializeDBRef(          buffer,          key,          value,          index,          depth,          serializeFunctions,        );      } else if (value instanceof BSONRegExp) {        index = serializeBSONRegExp(buffer, key, value, index);      } else if (value instanceof Int32) {        index = serializeInt32(buffer, key, value, index);      } else if (value instanceof MinKey || value instanceof MaxKey) {        index = serializeMinMax(buffer, key, value, index);      } else if (value instanceof Object) {        index = serializeObject(          buffer,          key,          value,          index,          checkKeys,          depth,          serializeFunctions,          ignoreUndefined,          false,          path,        );      } else {        throw new BSONTypeError(`Unrecognized or invalid BSON Type: ${value}`);      }    }  }
  // Remove the path  path.pop();
  // throw if index is out of bounds  if (buffer.length < index) {    throw new Error("Document exceeds max BSON size");  }
  // Final padding byte for object  buffer[index++] = 0x00;
  // Final size  const size = index - startingIndex;  // Write the size of the object  buffer[startingIndex++] = size & 0xff;  buffer[startingIndex++] = (size >> 8) & 0xff;  buffer[startingIndex++] = (size >> 16) & 0xff;  buffer[startingIndex++] = (size >> 24) & 0xff;  return index;}