Argthtjtr

I have a node app that I just started working with and each time I try to run it, it says there is a missing module. I've just been using npm install ... for each module but after doing about 10 of them I'm wondering if there is a way to have npm pull down all needed modules for a node app without me installing each one manually. Can it be done?

Yes, as long as the dependency is listed in package.json.

In the directory that contains package.json, just type:

npm install

I created an npm module to handle installing missing modules automatically.

npm-install-missing

It will install all app dependencies and sub-dependencies automatically. This is useful when submodules aren't installed correctly.

You can run npm install yourModule --save in order to install and automatically update package.json with this newly installed module.

So when you run npm install a second time it will install every dependecy previously added and you won't need to reinstall every dependency one by one.

I have written a script for this.

Place it at the start of your script, and any uninstalled modules will be installed when you run it.

(function () {

  var r = require

  require = function (n) {

    try {

      return r(n)

    } catch (e) {

      console.log(`Module "${n}" was not found and will be installed`)

      r('child_process').exec(`npm i ${n}`, function (err, body) {

        if (err) {

          console.log(`Module "${n}" could not be installed. Try again or install manually`)

          console.log(body)

          exit(1)

        } else {

          console.log(`Module "${n}" was installed. Will try to require again`)

          try{

            return r(n)

          } catch (e) {

            console.log(`Module "${n}" could not be required. Please restart the app`)

            console.log(e)

            exit(1)

          }

        }

      })

    }

  }

})()

I was inspired by @Aminadav Glickshtein's answer to create a script of my own that would synchronously install the needed modules, because his answer lacks these capabilities.

I needed some help, so I started an SO question here. You can read about how this script works there.
The result is as follows:

const cp = require('child_process')



const req = async module => {

  try {

    require.resolve(module)

  } catch (e) {

    console.log(`Could not resolve "${module}"nInstalling`)

    cp.execSync(`npm install ${module}`)

    await setImmediate(() => {})

    console.log(`"${module}" has been installed`)

  }

  console.log(`Requiring "${module}"`)

  try {

    return require(module)

  } catch (e) {

    console.log(`Could not include "${module}". Restart the script`)

    process.exit(1)

  }

}



const main = async () => {

  const http    = await req('http')

  const path    = await req('path')

  const fs      = await req('fs')

  const express = await req('express')



  // The rest of the app's code goes here

}



main()

And a one-liner (139 characters!). It doesn't globally define child_modules, has no last try-catch and doesn't log anything in the console:

const req=async m=>{let r=require;try{r.resolve(m)}catch(e){r('child_process').execSync('npm i '+m);await setImmediate(()=>{})}return r(m)}



const main = async () => {

  const http    = await req('http')

  const path    = await req('path')

  const fs      = await req('fs')

  const express = await req('express')



  // The rest of the app's code goes here

}



main()