Type checker for TypeScript application

Sushmita Parajuli, BSc

Master's thesis

Abstract:

Developers are starting to use Typescript, a typed dialect of JavaScript, to develop huge and complicated apps. JavaScript libraries are integrated into Typescript applications using declaration files, which are a typed description of their APIs. The standard public repository for these files is DefinitelyTyped. Volunteers manually populate and maintain the repository, which is error-prone and time-consuming. Inconsistencies between a declaration file and javascript implementation cause the Typescript IDE to give inaccurate feedback, which leads to inappropriate use of the underlying JavaScript library. This thesis presents typechecker, a script that assigns and checks for the types that are required by JavaScript libraries or static files. To evaluate the script, 2 JavaScript libraries and some API responses were run against the script. It has been found that some of the libraries are ignoring type related errors intentionally. As the demand of TypeScript on JavaScript application are increasing, it has been found that typechecker is beneficial for libraries which are not maintained frequently. The result of the thesis can be used for generating type guards, which verifies the types of data.

Keywords

TypeScript, React.js, Node.js, JavaScript, JSX, error handling, Types, Declaration Files

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 30. 3. 2022

Obhajoba závěrečné práce

• Vedúci: Ing. Jan Masner, Ph.D.

Czech University of Life Sciences Prague

Faculty of Economics and Management

Master programme / odbor:
Systems Engineering and Informatics / Informatics