From Logic to Toolchains: An Empirical Study of Bugs in the TypeScript Ecosystem

TL;DR

This empirical study of 633 bugs in TypeScript projects reveals that modern faults are mainly related to tooling, configuration, and integration issues, influenced by project complexity and dependencies, shifting fault profiles from traditional logic errors.

Contribution

First large-scale empirical analysis of bugs in TypeScript, highlighting the shift in fault types due to static typing and ecosystem evolution.

Findings

Tooling and configuration faults dominate bug reports.

Build complexity and dependencies correlate with fault types.

TypeScript reduces runtime errors but increases build and integration issues.

Abstract

TypeScript has rapidly become a popular language for modern web development, yet its effect on software faults remains poorly understood. This paper presents the first large-scale empirical study of bugs in real-world TypeScript projects. We analyze 633 bug reports from 16 popular open-source repositories to construct a taxonomy of fault types, quantify their prevalence, and relate them to project characteristics such as size, domain, and dependency composition. Our results reveal a fault landscape dominated not by logic or syntax errors but by tooling and configuration faults, API misuses, and asynchronous error-handling issues. We show that these categories correlate strongly with build complexity and dependency heterogeneity, indicating that modern failures often arise at integration and orchestration boundaries rather than within algorithmic logic. A longitudinal comparison with JavaScript studies shows that while static typing in TypeScript has reduced traditional runtime and type errors, it has shifted fragility toward build systems and toolchains. These findings offer new insight into how language design and ecosystem evolution reshape the fault profiles of large-scale software systems.