@discoveryjs/node-modules

An utility for scan and analyze packages in node_modules. It uses file system scan to determine which package physical instances are exactly installed in node_modules.

Is a part of Discovery.js projects.

How to use
API
- fetchNodeModules(basedir): Promise.<packages: Array>
- fetchNodeModules.analyzer(file, content, context)
Examples
License

How to use

Install:

npm install @discoveryjs/node-modules

Use:

const fetchNodeModules = require('@discoveryjs/node-modules');

fetchNodeModules('absolute/path/to/project').then(packages => {
    // do something with found packages
});

See examples below.

API

fetchNodeModules(basedir): Promise.<packages: Array>

Main function to fetch a package list for a specified basedir. The method check basedir for node_modules and package.json to retrieve a package list. When basedir is not specified process.cwd() is using. Root package.json is optional and used to determine which packages are using for development purposes only.

A list of packages contains each physical instance of packages. That is, if a package has several copies of itself (e.g. due to various versions) all of them will be in the list. Each entry has following properties:

name – value of name field in package.json
version – value of version field in package.json; can be null for root package.json
dev – boolean value, which true when a package is using for dev purposes only
path – relative to basedir path to a package. It can be used as an unique identifier of a package instance (and deps.resolved use the same values for a reference)
entry - relative to path path to an entry point module. It can be null when entry is not resolved
deps - list of entries from dependencies, peerDependencies and optionalDependencies sections of package.json. devDependencies are included for root package.json only. Each entry has following properties:
- type – one of prod, peer, optional or dev
- name - a key from a dependency section
- version - a value from a dependency section
- resolved - resolved path to a package. It can be used to find a physical instance of package it refers to. It may contain null, if no physical instance of package is not found (Note: that's a missed dependency for prod, peer and dev dependencies, but not a problem for optional).
packageJson - content of a package.json parsed with JSON.parse()

fetchNodeModules.analyzer(file, content, context)

Analyzer to use with @discoveryjs/scan-fs:

const scanFs = require('@discoveryjs/scan-fs');
const nodeModules = require('@discoveryjs/node-modules');

scanFs({
    ...
    rules: [
        ...
        {
            test: /\/package\.json$/,
            extract: nodeModules.analyzer
        }
    ]
});

Examples

const fetchNodeModules = require('@discoveryjs/node-modules');

fetchNodeModules(__dirname).then(modules => {
    const groupByName = modules.reduce(
        (map, entry) => map.set(entry.name, (map.get(entry.name) || []).concat(entry)),
        new Map()
    );

    // find packages with more than one physical instance
    // and sort by entry count from top to bottom
    const duplicates = [...groupByName]
        .filter(([, entries]) => entries.length > 1)
        .sort(([, a], [, b]) => b.length - a.length);
    
    // output findings
    duplicates.forEach(([name, entries]) => {
        console.log(`${name} (${entries.length} entries)`);
        entries.forEach(({ path, version }) => console.log(`  ${path} ${version}`));
    });
});

The same example but using jora:

const fetchNodeModules = require('@discoveryjs/node-modules');
const jora = require('jora');

fetchNodeModules(__dirname).then(modules => {
    const duplicates = jora(`
        group(<name>).({ name: key, entries: value })
        .[entries.size() > 1]
        .sort(<entries.size()>)
        .reverse()
    `)(modules);
    
    // output findings
    duplicates.forEach(({ name, entries }) => {
        console.log(`${name} (${entries.length} entries)`);
        entries.forEach(({ path, version }) => console.log(`  ${path} ${version}`));
    });
});

Example of output in both cases:

ansi-regex (2 entries)
  node_modules/ansi-regex 3.0.0
  node_modules/strip-ansi/node_modules/ansi-regex 4.1.0
resolve-from (2 entries)
  node_modules/resolve-from 5.0.0
  node_modules/import-fresh/node_modules/resolve-from 4.0.0
...

License

MIT