BSON parser

NOTE: This is usage documentation for the current 4.0.0 beta. You can find documentation for the 3.0 version of js-bson here

BSON is short for Binary JSON and is the binary-encoded serialization of JSON-like documents. You can learn more about it in the specification.

This browser version of the BSON parser is compiled using rollup and the current version is pre-compiled in the dist directory.

This is the default BSON parser, however, there is a C++ Node.js addon version as well that does not support the browser. It can be found at mongod-js/bson-ext.

Usage

To build a new version perform the following operations:

npm install
npm run build

A simple example of how to use BSON in the browser:

<script src="./dist/bson.js"></script>

<script>
  function start() {
    // Get the Long type
    const Long = BSON.Long;

    // Serialize document
    const doc = { long: Long.fromNumber(100) }

    // Serialize a document
    const data = BSON.serialize(doc)
    // De serialize it again
    const doc_2 = BSON.deserialize(data)
  }
</script>

A simple example of how to use BSON in Node.js:

const BSON = require('bson');
const Long = BSON.Long;

const doc = { long: Long.fromNumber(100) };

// Serialize a document
const data = BSON.serialize(doc);
console.log('data:', data);

// Deserialize the resulting Buffer
const doc_2 = BSON.deserialize(data);
console.log('doc_2:', doc_2);

Installation

npm install bson

Documentation

Objects

EJSON : object

Functions

setInternalBufferSize(size): Sets the size of the internal serialization buffer.
serialize(object) ⇒ Buffer: Serialize a Javascript object.
serializeWithBufferAndIndex(object, buffer) ⇒ Number: Serialize a Javascript object using a predefined Buffer and index into the buffer, useful when pre-allocating the space for serialization.
deserialize(buffer) ⇒ Object: Deserialize data as BSON.
calculateObjectSize(object) ⇒ Number: Calculate the bson size for a passed in Javascript object.
deserializeStream(data, startIndex, numberOfDocuments, documents, docStartIndex, [options]) ⇒ Number: Deserialize stream data as BSON documents.

EJSON

EJSON

EJSON.parse(text, [options])

Param	Type	Default	Description
text	`string`
[options]	`object`		Optional settings
[options.relaxed]	`boolean`	`true`	Attempt to return native JS types where possible, rather than BSON types (if true)

Parse an Extended JSON string, constructing the JavaScript value or object described by that string.

Example

const { EJSON } = require('bson');
const text = '{ "int32": { "$numberInt": "10" } }';

// prints { int32: { [String: '10'] _bsontype: 'Int32', value: '10' } }
console.log(EJSON.parse(text, { relaxed: false }));

// prints { int32: 10 }
console.log(EJSON.parse(text));

EJSON.stringify(value, [replacer], [space], [options])

Param	Type	Default	Description
value	`object`		The value to convert to extended JSON
[replacer]	`function` \| `array`		A function that alters the behavior of the stringification process, or an array of String and Number objects that serve as a whitelist for selecting/filtering the properties of the value object to be included in the JSON string. If this value is null or not provided, all properties of the object are included in the resulting JSON string
[space]	`string` \| `number`		A String or Number object that's used to insert white space into the output JSON string for readability purposes.
[options]	`object`		Optional settings
[options.relaxed]	`boolean`	`true`	Enabled Extended JSON's `relaxed` mode

Converts a BSON document to an Extended JSON string, optionally replacing values if a replacer function is specified or optionally including only the specified properties if a replacer array is specified.

Example

const { EJSON } = require('bson');
const Int32 = require('mongodb').Int32;
const doc = { int32: new Int32(10) };

// prints '{"int32":{"$numberInt":"10"}}'
console.log(EJSON.stringify(doc, { relaxed: false }));

// prints '{"int32":10}'
console.log(EJSON.stringify(doc));

EJSON.serialize(bson, [options])

Param	Type	Description
bson	`object`	The object to serialize
[options]	`object`	Optional settings passed to the `stringify` function

Serializes an object to an Extended JSON string, and reparse it as a JavaScript object.

EJSON.deserialize(ejson, [options])

Param	Type	Description
ejson	`object`	The Extended JSON object to deserialize
[options]	`object`	Optional settings passed to the parse method

Deserializes an Extended JSON object into a plain JavaScript object with native/BSON types

setInternalBufferSize(size)

Param	Type	Description
size	`number`	The desired size for the internal serialization buffer

Sets the size of the internal serialization buffer.

serialize(object)

Param	Type	Default	Description
object	`Object`		the Javascript object to serialize.
[options.checkKeys]	`Boolean`		the serializer will check if keys are valid.
[options.serializeFunctions]	`Boolean`	`false`	serialize the javascript functions (default:false).
[options.ignoreUndefined]	`Boolean`	`true`	ignore undefined fields (default:true).

Serialize a Javascript object.

Returns: Buffer - returns the Buffer object containing the serialized object.

serializeWithBufferAndIndex(object, buffer)

Param	Type	Default	Description
object	`Object`		the Javascript object to serialize.
buffer	`Buffer`		the Buffer you pre-allocated to store the serialized BSON object.
[options.checkKeys]	`Boolean`		the serializer will check if keys are valid.
[options.serializeFunctions]	`Boolean`	`false`	serialize the javascript functions (default:false).
[options.ignoreUndefined]	`Boolean`	`true`	ignore undefined fields (default:true).
[options.index]	`Number`		the index in the buffer where we wish to start serializing into.

Serialize a Javascript object using a predefined Buffer and index into the buffer, useful when pre-allocating the space for serialization.

Returns: Number - returns the index pointing to the last written byte in the buffer.

deserialize(buffer)

Param	Type	Default	Description
buffer	`Buffer`		the buffer containing the serialized set of BSON documents.
[options.evalFunctions]	`Object`	`false`	evaluate functions in the BSON document scoped to the object deserialized.
[options.cacheFunctions]	`Object`	`false`	cache evaluated functions for reuse.
[options.cacheFunctionsCrc32]	`Object`	`false`	use a crc32 code for caching, otherwise use the string of the function.
[options.promoteLongs]	`Object`	`true`	when deserializing a Long will fit it into a Number if it's smaller than 53 bits
[options.promoteBuffers]	`Object`	`false`	when deserializing a Binary will return it as a node.js Buffer instance.
[options.promoteValues]	`Object`	`false`	when deserializing will promote BSON values to their Node.js closest equivalent types.
[options.fieldsAsRaw]	`Object`		allow to specify if there what fields we wish to return as unserialized raw buffer.
[options.bsonRegExp]	`Object`	`false`	return BSON regular expressions as BSONRegExp instances.
[options.allowObjectSmallerThanBufferSize]	`boolean`	`false`	allows the buffer to be larger than the parsed BSON object

Deserialize data as BSON.

Returns: Object - returns the deserialized Javascript Object.

calculateObjectSize(object)

Param	Type	Default	Description
object	`Object`		the Javascript object to calculate the BSON byte size for.
[options.serializeFunctions]	`Boolean`	`false`	serialize the javascript functions (default:false).
[options.ignoreUndefined]	`Boolean`	`true`	ignore undefined fields (default:true).

Calculate the bson size for a passed in Javascript object.

Returns: Number - returns the number of bytes the BSON object will take up.

deserializeStream(data, startIndex, numberOfDocuments, documents, docStartIndex, [options])

Param	Type	Default	Description
data	`Buffer`		the buffer containing the serialized set of BSON documents.
startIndex	`Number`		the start index in the data Buffer where the deserialization is to start.
numberOfDocuments	`Number`		number of documents to deserialize.
documents	`Array`		an array where to store the deserialized documents.
docStartIndex	`Number`		the index in the documents array from where to start inserting documents.
[options]	`Object`		additional options used for the deserialization.
[options.evalFunctions]	`Object`	`false`	evaluate functions in the BSON document scoped to the object deserialized.
[options.cacheFunctions]	`Object`	`false`	cache evaluated functions for reuse.
[options.cacheFunctionsCrc32]	`Object`	`false`	use a crc32 code for caching, otherwise use the string of the function.
[options.promoteLongs]	`Object`	`true`	when deserializing a Long will fit it into a Number if it's smaller than 53 bits
[options.promoteBuffers]	`Object`	`false`	when deserializing a Binary will return it as a node.js Buffer instance.
[options.promoteValues]	`Object`	`false`	when deserializing will promote BSON values to their Node.js closest equivalent types.
[options.fieldsAsRaw]	`Object`		allow to specify if there what fields we wish to return as unserialized raw buffer.
[options.bsonRegExp]	`Object`	`false`	return BSON regular expressions as BSONRegExp instances.

Deserialize stream data as BSON documents.

Returns: Number - returns the next index in the buffer after deserialization x numbers of documents.

FAQ

Why does `undefined` get converted to `null`?

The undefined BSON type has been deprecated for many years, so this library has dropped support for it. Use the ignoreUndefined option (for example, from the driver ) to instead remove undefined keys.

How do I add custom serialization logic?

This library looks for toBSON() functions on every path, and calls the toBSON() function to get the value to serialize.

const BSON = require('bson');

class CustomSerialize {
  toBSON() {
    return 42;
  }
}

const obj = { answer: new CustomSerialize() };
// "{ answer: 42 }"
console.log(BSON.deserialize(BSON.serialize(obj)));

clarkttfu/js-bson