Language Support

Hotspots supports seven languages. All produce the same metrics (CC, ND, FO, NS, LRS) with consistent semantics.

Supported languages

Language	File extensions
TypeScript	.ts .tsx .mts .cts
JavaScript	.js .jsx .mjs .cjs
Go	.go
Python	.py
Rust	.rs
Java	.java
C	.c .h

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Language notes

TypeScript / JavaScript

JSX and TSX are fully supported. Short-circuit operators (&&, ||) and ternaries count toward CC. Arrow functions, class methods, and standalone functions are all analyzed.

Arrow functions and function expressions assigned to a variable or property are named after their binding — const validate = (x) => … appears in output as validate, not as an anonymous function. This applies to .ts, .tsx, .mts, and .cts files.

Go

Goroutines, defer, select, and channel operations are supported. Each case in a select counts toward CC.

Python

Async/await, comprehensions, context managers, and match statements (Python 3.10+) are supported. Comprehensions with conditionals contribute to CC.

Rust

match arms, ? operator, unwrap/expect, closures, and impl blocks are supported. Each match arm counts toward CC.

Java

Java 8+ including lambdas, streams, try-with-resources, and switch expressions (Java 14+). Lambda bodies are analyzed as separate scopes.

C

Standard C with support for all control flow constructs: if/else, switch, for, while, do/while, goto. Ternary operators and boolean short-circuit operators (&&, ||) count toward CC. Header files are analyzed when function definitions are present.

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What counts as a function

Hotspots analyzes named, callable units of code:

• Named functions and methods
• Class methods and constructors
• Arrow functions assigned to a named variable or property
• Closures assigned to a named binding

Anonymous inline functions (callbacks passed directly to .map() or similar) are not analyzed as standalone units — their complexity folds into the containing named function's FO count.

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Exclusions

Hotspots automatically skips:

• Test files (*.test.*, *_test.*, *spec*, tests/, __tests__/)
• Vendored dependencies (vendor/, node_modules/, third_party/, external/, contrib/, deps/)
• Generated files (detected by heuristic — minified files, protobuf output, etc.)
• Type declaration files (.d.ts)

Override exclusions in .hotspotsrc.json with exclude patterns. See Configuration.