Node.js function to get the names of all devDependencies in a yarn or lerna workspace

get-dev-dependencies.js

module.exports = async function getDevDependencies(globs = ['package.json', 'packages/*/*.json']) {
    const globby = require('globby');
    const packageFiles = await globby(globs, { absolute: true });

    return packageFiles.reduce((result, file) => {
        const pkg = require(file);
        if (pkg.devDependencies) {
            const names = Object.keys(pkg.devDependencies);
            return result.concat(names.filter(name => !result.includes(name)));
        }
        return result;
    }, []).sort();
}

usage-example.js

(async () => {
    const getDevDependencies = require('./get-dev-dependencies');
    const devDependencies = await getDevDependencies(['package.json', 'client/*/*.json', 'server/*/*.json']);
    console.log(devDependencies)
})();

yarn-prune-workspace.js

// see https://gist.github.com/pxwise/c4833557930a5141c4e3c752347e2f2e

/**
 * Approximate `npm prune --production` using `yarn remove`.
 * @see https://github.com/yarnpkg/yarn/issues/696
 */
const exec = require('child_process').exec;
const getDevDependencies = require('./get-dev-dependencies');

(async () => {
  // given a package.json with "workspaces": ["client/*", "server/*"]
  const devDependencies = await getDevDependencies(['package.json', 'client/*/*.json', 'server/*/*.json']).join(', ');
  const command = 'yarn remove ' + devDependencies;

  const child = exec(command, (err, stdout, stderr) => {
    if (err) throw err;
    console.log(`stdout: \n${stdout}`);
    console.log(`stderr: \n${stderr}`);
  });

})();