MongoDB Stitch Extended JSON Library

The MongoDB Extended JSON Library allows you to convert MongoDB documents to Extended JSON, and vice versa. See the Extended JSON specification here.

Usage with MongoDB Driver

This library can be used along with the MongoDB driver for Node.js to convert MongoDB documents to extended JSON form.

Serialize a document

Serialize a document using EJSON.stringify(value, reducer, indents, options). The reducer and indents arguments are analogous to JSON.stringify's replacer and spaces arguments, respectively (see documentation.)

options currently supports a single option, relaxed; with options = {relaxed: true}, the returned object will be in the more readable "relaxed" extended JSON format.

let EJSON = require('mongodb-stitch-extjson'),
	Int32 = require('mongodb').Int32;
    
var doc = { int32: new Int32(10) };

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

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

Usage with MongoDB BSON Library

Our js-bson library is included as a dependency and used by default for Javascript representations of BSON types. See the next section for instructions on using it with a different BSON library.

Serialize a document

This works identically to the previous serialize example, but does not require including the MongoDB driver. The BSON types are all available under EJSON.BSON.

let EJSON = require('mongodb-stitch-extjson'),
	Int32 = EJSON.BSON.Int32;
    
var doc = { int32: new Int32(10) };

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

Deserialize a document

The library also allows converting extended JSON strings to Javascript objects, using BSON type classes defined in js-bson. You can do this using EJSON.parse(string, options).

This method supports the option strict. By default, strict is true; if strict is set to false, the parser will attempt to return native JS types where possible, rather than BSON types (i.e. return a Number instead of a BSON.Int32 object, etc.)

let EJSON = require('mongodb-stitch-extjson');

var text = '{"int32":{"$numberInt":"10"}}';

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

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

Usage With Other BSON Parsers

Although we include the pure Javascript BSON parser by default, you can also use a different BSON parser with this library, such as bson-ext. For example:

let EJSON = require('mongodb-stitch-extjson'),
	BSON = require('bson-ext'),
    Int32 = BSON.Int32;

// set BSON module to be bson-ext 
EJSON.setBSONModule(BSON);

var doc = { int32: new Int32(10) };
// prints '{"int32":{"$numberInt":"10"}}'
console.log(EJSON.stringify(doc));

var text = '{"int32":{"$numberInt":"10"}}';
// prints { int32: { [String: '10'] _bsontype: 'Int32', value: '10' } }
console.log(EJSON.parse(text));

FAQ

What are the various files in dist?

• ejson.bundle.js is a bundled up version of the library that is suitable for inclusion in an HTML page via a <script> tag.
• ejson.esm.js is a rolled up version of the library that is suitable for interoperation with bundlers that work better with ES modules.
• ejson.browser.esm.js is similar to ejson.esm.js but is ultimately intened for consumers producing browser bundles. It also pulls in any browser specific dependencies/code that may be needed.
• ejson.browser.umd.js is similar to the source code of this library but is ultimately intened for consumers producing browser bundlers expecting a UMD format. It also pulls in any browser specific dependencies/code that may be needed.