The best way to run npm install for nested folders?

Question

What is the most correct way to install npm packages in nested sub folders?

my-app
  /my-sub-module
  package.json
package.json

<

Answer 1

My solution is very similar. Pure Node.js

The following script examines all subfolders (recursively) as long as they have package.json and runs npm install in each of them. One can add exceptions to it: folders allowed not having package.json. In the example below one such folder is "packages". One can run it as a "preinstall" script.

const path = require('path')
const fs = require('fs')
const child_process = require('child_process')

const root = process.cwd()
npm_install_recursive(root)

// Since this script is intended to be run as a "preinstall" command,
// it will do `npm install` automatically inside the root folder in the end.
console.log('===================================================================')
console.log(`Performing "npm install" inside root folder`)
console.log('===================================================================')

// Recurses into a folder
function npm_install_recursive(folder)
{
    const has_package_json = fs.existsSync(path.join(folder, 'package.json'))

    // Abort if there's no `package.json` in this folder and it's not a "packages" folder
    if (!has_package_json && path.basename(folder) !== 'packages')
    {
        return
    }

    // If there is `package.json` in this folder then perform `npm install`.
    //
    // Since this script is intended to be run as a "preinstall" command,
    // skip the root folder, because it will be `npm install`ed in the end.
    // Hence the `folder !== root` condition.
    //
    if (has_package_json && folder !== root)
    {
        console.log('===================================================================')
        console.log(`Performing "npm install" inside ${folder === root ? 'root folder' : './' + path.relative(root, folder)}`)
        console.log('===================================================================')

        npm_install(folder)
    }

    // Recurse into subfolders
    for (let subfolder of subfolders(folder))
    {
        npm_install_recursive(subfolder)
    }
}

// Performs `npm install`
function npm_install(where)
{
    child_process.execSync('npm install', { cwd: where, env: process.env, stdio: 'inherit' })
}

// Lists subfolders in a folder
function subfolders(folder)
{
    return fs.readdirSync(folder)
        .filter(subfolder => fs.statSync(path.join(folder, subfolder)).isDirectory())
        .filter(subfolder => subfolder !== 'node_modules' && subfolder[0] !== '.')
        .map(subfolder => path.join(folder, subfolder))
}