Designing Web Application Client Program Modules for Asynchronous Event Handling

The article considers possible approaches to designing program modules in web application clients. A design approach is proposed, the use of which provides an increase in the ease of debugging programs in the development process, localization of errors and reduction of program code duplication. The proposed design approach is based on the division of responsibility between parts of the program code for the implementation of synchronous and asynchronous operations in asynchronous events. Responsibility for processing network interaction with the server and receiving data from the user through controls in the user interface should be assigned to asynchronous operations and their responsibility should be limited only to receiving data from external sources. In turn, updating the application state based on data from external sources should be limited to the responsibility of synchronous operations. The paper shows how the proposed design approach provides the above improvements and provides examples of program code.