Challenge: Process JSON Data

Problem statement

For this challenge, complete the getMostExpensive function below. The function takes in a JSON string as input, and it should be able to first convert the passed string to some data structure based on the Item type. It should then traverse the items to find the most expensive item and return it in the JSON string format.

Sample input

The input to getMostExpensive function is a string representing items in JSON. Each item has a title and price. A sample value is shown below: