Monorepo support?

Feature request description

I am wondering if we want to support monorepos out of the box. We could look for all package.json files.

Code snippets (if applicable)

#!/usr/bin/env node

const depcheck = require('depcheck');
const glob = require('globby');
const fs = require('fs');
const path = require('path');

const IGNORE_PACKAGES = [
];

const rootDir = path.resolve(__dirname, '../');

const getPackages = async () => {
  const packages = await glob('**/package.json', { ignore: ['**/node_modules/**'] });
  if (packages.length === 0) {
    throw new Error('Did not find \'packages\'');
  }
  const PackageContent = [];
  packages.forEach(packagePath =>  {
    try {
      const packageJsonString = fs.readFileSync(packagePath, 'utf8');
      const packageJson = JSON.parse(packageJsonString);

      const pathToPackageJson = `${rootDir}/${packagePath}`;

      const pkg = {
        location: path.dirname(pathToPackageJson),
        name: packageJson.name,
      };
      PackageContent.push(pkg);
    } catch (err) {
      console.log(`Couldn't find a 'package.json' for ${packagePath}. Skipping. ${err}`);
    }
  });
  return PackageContent;
};

(async () => {
  console.log('*** NOTE: Double check usage before removing a package***');
  const packages = await getPackages().catch(err => {
    console.log(`Error in getPackages ${err}`);
  });

  const unusedPackages = [];

  for (const pkg of packages) {

    console.log(`\nChecking ${pkg.name} for unused deps.`);

    const opts = {
    };


    const results = await depcheck(pkg.location, opts);
    const individualPackageDeps = results.dependencies.filter(dep => !IGNORE_PACKAGES.includes(dep));

    if (individualPackageDeps.length !== 0) {
      console.log(individualPackageDeps.join('\r\n'));
      unusedPackages.push(...individualPackageDeps);
    }

  }
  if (unusedPackages.length !== 0 ) {
    console.log(`\nYou have unused packages: \n${unusedPackages.join('\r\n')}\n` );
    process.exit(1);
  }

})().catch(err => { console.log(err);});

Any extra info

We could either just include this example in the docs or make it the default functionality. What do you think?

[rumpl]

Wait what, no! I mean yeah, we can close this one since it’s a duplicate of #245 but we should support yarn workspaces, I’m OK if we support only the mode 1 that @benjie suggested.

[benjie]

I suggest you only support mode 1. Typically mode 2 is only used for repo-wide tooling such as lerna itself, eslint, etc. Mode 2 is actually super dangerous to support if you’re planning to publish to npm because it can hide the fact that dependencies are missing on individual packages.

I don’t think we need support for lerna; I use it with graphile-engine but I don’t think depcheck would even need to know it exists to validate the repo with yarn workspaces.