What is the primary function of JSON.parse?

The primary function of JSON.parse is to convert a JSON string into a JavaScript object. This method takes a string formatted in JSON (JavaScript Object Notation) and transforms it into a corresponding JavaScript object, enabling developers to easily work with structured data received from external sources such as APIs.

Using JSON.parse allows for the interpretation of the JSON string's data structure, translating it into an object that can be manipulated with standard JavaScript syntax. This is particularly useful when handling data from a server or other external sources, as it facilitates dynamic data manipulation within an application.

The other options refer to actions that JSON.parse does not perform. Converting JavaScript values to a JSON string corresponds to JSON.stringify, creating a JSON string from a JavaScript function is not a standard operation in JSON handling, and updating existing JavaScript objects with JSON data would involve additional methods but is not the primary function of JSON.parse. Hence, option B accurately describes the main utility of the JSON.parse method.