In today's session, we’re diving into a practical task that involves working with strings to create and manipulate nested objects. Such tasks are common in many real-world applications, where parsing and updating data structures dynamically is crucial. We'll learn how to transform a complex string into a nested object and then update specific values within it. By the end of this lesson, you'll have a solid understanding of string parsing and nested object manipulation.

We need to transform a given complex string into a nested object and update a specific key-value pair within that object. The input string will be in the format "Key1=Value1,Key2=Value2,...". If the value part of a key-value pair contains another key-value string, it should be represented as a nested object.

For example, the input string "A1=B1,C1={D1=E1,F1=G1},I1=J1" should be converted into the following nested object:

After parsing this string into the nested object, we'll update the value of the nested key F1 from G1 to a new value, such as NewValue. The function should ultimately return the updated object.

To tackle this problem, we will take the following steps:

• Initialize Variables and Data Structures: Set up variables and data structures necessary for parsing the string and handling nested objects with TypeScript-specific type annotations.