ReScriptDep

A dependency analyzer for ReScript modules.

Introduction

ReScriptDep is a tool for analyzing dependencies between ReScript modules. It uses cmt files to identify module dependencies and can visualize them or output them in JSON format.

Installation

# Install via opam
opam install rescriptdep

Building with Static Linking (Linux)

To build rescriptdep with static linking on Linux, which creates a standalone executable without external dependencies:

# Build the project using the static profile
dune build --profile static

# This will generate a statically linked executable for Linux environments

Usage

# Basic usage
rescriptdep [options] files_or_dirs

# Options
# -o, --output <file>         : Output file (default: stdout)
# -f, --format <format>       : Output format (dot, json)
# -m, --module <name>         : Focus on specific module and its dependencies
# -v, --verbose               : Enable verbose output
# -b, --benchmark             : Enable performance benchmarking
# --no-cache                  : Skip using cache
# --clear-cache               : Clear the cache before analyzing
# -nd, --no-dependents        : Find modules that have no dependents (not imported by any other modules)
# -vb, --value-binding <name> : Count usage of a value binding (by name) across the project (in the module itself and all dependents; requires -m)
# -vl, --value-line <line>    : Line number of the value binding (1-based, for disambiguation when multiple bindings have the same name; use with -vb)

files_or_dirs are compiled .cmt files or directories that contain them, usually the project's lib/bs.

With -vb, each module reports its usage count, or a negative code when it could not be analyzed: -2 no implementation, -3 unreadable .cmt file, -4 no .cmt file, -5 no file path, -6 the compiler that built the module is not supported by value usage analysis.

Supported ReScript Versions

ReScript	Dependency graph	Value usage (-vb)
11.0.0 - 11.1.4	Yes	Yes
12.0.0 - 12.3.1	Yes	Yes
13.0.0-alpha.1 - alpha.3, alpha.5, alpha.6	Yes	Yes
13.0.0-alpha.4	Yes	No (-6), see below

rescriptdep identifies the compiler from each .cmt file and, for ReScript 12 and later, from the version rewatch records in lib/bs/compiler-info.json. Files in formats no supported compiler writes are rejected with an error instead of being misread. Other versions of a supported format (for example a later 13.0 prerelease) get the dependency graph, and -6 from -vb until their typed tree has been checked.

ReScript 13.0.0-alpha.4

Value usage analysis (-vb, the inline "Used N times" count in the VS Code extension) is not supported for projects built with 13.0.0-alpha.4, and every module reports -6. The dependency graph works as usual.

-vb reads the typed tree stored in .cmt files, which depends on the exact layout of the compiler's data types. 13.0.0-alpha.4 inserted the for...of constructors in the middle of the expression type, a layout no other release uses: 13.0.0-alpha.5 moved them to the end of the type. Rather than keep a decoder for that single prerelease, rescriptdep skips it. Upgrade to 13.0.0-alpha.5 or later to use value usage analysis.

Development

For detailed information about building the project, running tests, and contributing, please see CONTRIBUTING.md.

Quick Start for Development

# Build the project
make build

# Run the CI-equivalent test suite (requires pnpm 10.x)
make test

License

MIT