Prune.js

Prune.js is a tool created to detect dead code in JavaScript projects using ECMAScript 6.

About prune.js

This tool is part of the output of my MSc. Software Engineering at the University of Amsterdam. The research is focused in the detection of dead code in ECMAScript 6 projects using static analysis. The code is provided as a reference with the intention to verify the results obtained and for future work.

Related material

• threkk/prune.js-paper: This repository contains the TeX files for the paper of the project.
• threkk/prune.js-presentation: Slides used during the presentation of the project.
• threkk/prune.js-material: Repository with the material used in the examples in the paper.
• threkk/dead-code-example: Example project to run prune.js against.

Getting started

The project requires the latest stable version of Node.js to run, although it is highly likely that it will run in any version of Node.js but not compile.

$ git clone https://github.com/threkk/prune.js
$ npm install
$ npm run build

# If you want to install it locally
$ npm link
$ prunejs

# If you just want to run it
$ npm run prunejs

How to use

The tool takes two inputs. The first one is a command, and the second is a configuration file. There are three commands available:

• dead-code: Runs the tool in dead code detection mode. It will return three lists: one for dependencies, one for the modules and one for the statements.
• project-graph: Prints a call graph of the whole project in Graphviz format.
• file-graph: Prints a call graph of the module passed as a path in the third parameter.

Configuration file

The second input is a configuration file with some information for the project that is necessary to run the tool. The file is a JavaScript file with the following format:

module.exports = {
  root: '~/code/my-project',
  ignore: ['./docs/'],
  entryPoints: ['./src/index.js'],
}

• root: Path where the project is located.
• entryPoints: List of paths that point to the entry points of the project.
• ignore: List of paths to ignore when executing the project.
• isLibrary: Boolean that indicates if the project should be analysed as an external library which is expected to be consumed.