ack-webpack/promiseSpawn.function.js

A code bundler that drastically reduces setup time by offering an init prompt of project setup questions and includes a fantastic browser reloader.

const ackPath = require('ack-path')
const childProcess = require('child_process')
const spawn = childProcess.spawn;
const windows = process.platform === 'win32'

const spawnOptions = {
  cwd: process.cwd(),
  env: process.env,
  shell:windows
}

function filterArgs(args){
  return args.map(value=>escape(value))
}

/**
  @options - {
    log:optional, typically console.log.bind(console)
  }
*/
function promiseSpawn(sArgs, options){
  return new Promise((res,rej)=>{
    const dataArray = []

    if(windows){
      sArgs = filterArgs(sArgs)
    }

    const command = sArgs.shift()
    const ls = spawn(command, sArgs, spawnOptions);
    var spawnError = null

    const upgradeError = err=>{
      if(!err)return err

      if(err.message){
        let msg = err.msg
        msg += '\ncommand-args:'+ JSON.stringify(sArgs)
        err = new Error(msg)
      }else if(err.split){
        let msg = err
        msg += '\ncommand-args:'+ JSON.stringify(sArgs)
        err = new Error(msg)
      }

      return err
    }

    let onData = data=>dataArray.push(data)
    let onError = err=>spawnError=err

    if(options && options.log){
      onData = data=>dataArray.push(data) && options.log(data.toString())
      onError = err=>spawnError=err && options.log(err)
    }
    
    ls.stdout.on('data', onData)
    ls.stdout.on('error', onError)
    ls.stderr.on('data', onData)
    ls.stderr.on('error', onError)

    ls.on('close', code=>{
      if(spawnError){
        return rej( upgradeError(spawnError) )
      }

      const output = dataArray.join('')//bring all cli data together

      if(options && options.log){
        options.log( output )
      }

      res( output )
    })
  })
}
module.exports = promiseSpawn

module.exports.installPacks = function(packs, options){
  let promise = Promise.resolve()
  packs.forEach( pack=>promise=promise.then(()=>installer(pack,options)) )
  return promise
}

function installer(name, options){
  const args = ['npm','install','--save-dev',name]
  return promiseSpawn(args, options)
}
module.exports.installer = installer

function isModuleInstalled(name){
  try{
    require(name)
    return true
  }catch(e){
    const isNotFoundError = e && e.message.match('Cannot find module')
    
    if(isNotFoundError){
      return ackPath( process.cwd() ).join('node_modules',name).sync().exists()
    }

    return true
  }
}
module.exports.isModuleInstalled = isModuleInstalled