In Vue-CLI run dev, fail. - npm

Question

In the vue-cli, I want to npm run dev, but get the bellow error:
$ npm run dev
> vuejs-playlist#1.0.0 dev /Users/den/Desktop/Test/vue/vuejs-playlist
> cross-env NODE_ENV=development webpack-dev-server --open --hot
sh: cross-env: command not found
npm ERR! file sh
npm ERR! code ELIFECYCLE
npm ERR! errno ENOENT
npm ERR! syscall spawn
npm ERR! vuejs-playlist#1.0.0 dev: `cross-env NODE_ENV=development webpack-dev-server --open --hot`
npm ERR! spawn ENOENT
npm ERR!
npm ERR! Failed at the vuejs-playlist#1.0.0 dev script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?
npm ERR! A complete log of this run can be found in:
npm ERR! /Users/den/.npm/_logs/2018-02-02T11_54_11_067Z-debug.log

Answer 1

Try as follows for #vue/cli
npm run serve

Answer 2

In your traceback:
Local package.json exists, but node_modules missing, did you mean to install?
You should in your project root directory install the dependencies:
npm install
Or use its logogram npm i

Answer 3

As both answers before stated your build failed due needing to first:
npm install
Once that is complete, check your package.json file.
In there will have the default options for npm run followed by your build script option.
Example:
{
"scripts": {
"serve": "vue-cli-service serve",
"build": "vue-cli-service build"
}
}
Resulting in your npm run serve is the same as vue-cli-service serve
Reference: Vue Docs