You can simply use JSON.parse.

The definition of the JSON object is part of the ECMAScript 5 specification. node.js is built on Google Chrome's V8 engine, which adheres to ECMA standard. Therefore, node.js also has a global object JSON [docs].

Note - JSON.parse can tie up the current thread because it is a synchronous method. So if you are planning to parse big JSON objects use a streaming json parser.