Angular2 : concurrent is not recognized as internal or external command

Question

While running server for angular2 using npm start is giving error that concurrent is not recognized as internal or external command, why is it happens these kind of error

here is package.json:

{
  "name": "contactlistapp",
  "version": "1.0.0",
  "description": "The app",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "tsc": "./node_modules/.bin/tsc",
    "tsc:w": "./node_modules/.bin/tsc -w",
    "serve": "./node_modules/.bin/live-server --host=localhost --port=3000 .",
    "start": "concurrent \"npm run tsc:w\" \"npm run serve\" "
  },
  "author": "Sarah",
  "license": "ISC",
  "dependencies": {
    "express": "^4.13.3",
    "angular2": "2.0.0-beta.0",
    "systemjs": "0.19.6",
    "es6-promise": "^3.0.2",
    "es6-shim": "^0.33.3",
    "reflect-metadata": "0.1.2",
    "rxjs": "5.0.0-beta.0",
    "zone.js": "0.5.10"
  },
  "devDependencies": {
    "concurrently": "^1.0.0",
    "lite-server": "^1.3.1",
    "typescript": "^1.7.3"
  }
}

structure of the project is there is node_module and typings folder there is app.ts file for server(empty only express is imported), and component.ts(and their .js), tsconfig.json

Solution

concurrent is not recognized as internal or external command

Must likely you haven't ran npm install since you added the "concurrently": "^1.0.0" dependency.

live-server is not recognized as external or internal command

You are installing the lite-server :

"lite-server": "^1.3.1"

yet you are calling the live-server:

"serve": "./node_modules/.bin/live-server --host=localhost --port=3000 ."

call lite-server instead.