Dev watchers stops on error

[peter-mach]

Steps to reproduce

1). run npm run dev
2). make error in the source-code

What is happening

After running npm run dev and making the error in the source code the watchers stop.

Expected behaviour

Watchers continue to watch for errors and try to build the projects after every change.

Log:

  angular2-universal-starter  npm run dev

> angular2-universal-starter@0.5.0 dev /Users/Julia/Work/angular2/angular2-universal-starter
> node tools/dev.js

ts-loader: Using typescript@1.7.5 and /Users/Julia/Work/angular2/angular2-universal-starter/tsconfig.json
ts-loader: Using typescript@1.7.5 and /Users/Julia/Work/angular2/angular2-universal-starter/tsconfig.json
ts-loader: Using typescript@1.7.5 and /Users/Julia/Work/angular2/angular2-universal-starter/tsconfig.json
Hash: c1c43125aa3c80a4e4d508cc80c1ba06c0f19b105620da56d03235c52baa
Version: webpack 1.12.13
Child
    Hash: c1c43125aa3c80a4e4d5
    Version: webpack 1.12.13
    Time: 11822ms
        Asset    Size  Chunks             Chunk Names
    server.js  100 kB       0  [emitted]  server
       [0] multi server 28 bytes {0} [built]
        + 58 hidden modules
Child
    Hash: 08cc80c1ba06c0f19b10
    Version: webpack 1.12.13
    Time: 9949ms
        Asset     Size  Chunks             Chunk Names
    worker.js  1.69 MB       0  [emitted]  worker
       [0] multi worker 40 bytes {0} [built]
        + 188 hidden modules
Child
    Hash: 5620da56d03235c52baa
    Version: webpack 1.12.13
    Time: 12750ms
            Asset     Size  Chunks             Chunk Names
    worker_app.js  2.59 MB       0  [emitted]  worker_app
       [0] multi worker_app 28 bytes {0} [built]
        + 234 hidden modules
webpack: bundle is now VALID.
webpack: bundle is now INVALID.
undefined:1479
        return map[req] || (function() { throw new Error("Cannot find module '" + req + "'.") }());
                                         ^

Error: Cannot find module 'undefined'.
    at eval (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:1479:42)
    at webpackContextResolve (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:1479:90)
    at webpackContext (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:1476:30)
    at Object.eval (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:178:40)
    at __webpack_require__ (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:23:30)
    at Object.eval (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:104:14)
    at __webpack_require__ (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:23:30)
    at Object.eval (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:59:13)
    at __webpack_require__ (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:23:30)
    at Object.eval (eval at recompileApp (/Users/Julia/Work/angular2/angular2-universal-starter/tools/dev.js:62:3), <anonymous>:50:19)

npm ERR! Darwin 14.5.0
npm ERR! argv "/usr/local/Cellar/node/5.4.1_1/bin/node" "/usr/local/bin/npm" "run" "dev"
npm ERR! node v5.4.1
npm ERR! npm  v3.5.3
npm ERR! code ELIFECYCLE
npm ERR! angular2-universal-starter@0.5.0 dev: `node tools/dev.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the angular2-universal-starter@0.5.0 dev script 'node tools/dev.js'.
npm ERR! Make sure you have the latest version of node.js and npm installed.
npm ERR! If you do, this is most likely a problem with the angular2-universal-starter package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     node tools/dev.js
npm ERR! You can get information on how to open an issue for this project with:
npm ERR!     npm bugs angular2-universal-starter
npm ERR! Or if that isn't available, you can get their info via:
npm ERR!     npm owner ls angular2-universal-starter
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /Users/Julia/Work/angular2/angular2-universal-starter/npm-debug.log
➜  angular2-universal-starter