An ejected project cannot use the build command anymore
open the angular-cli.json, you should see this at the top
"project": { "name": "proj-name", "ejected": true,}remove the ejected part and it should work
once you ejected the project you will get a webpack.config file
And also you can see some commands in package.json script tag
"scripts": {"ng": "ng","start": "webpack-dev-server --port=4200","build": "webpack","test": "karma start ./karma.conf.js","lint": "ng lint","e2e": "protractor ./protractor.conf.js","pree2e": "webdriver-manager update --standalone false --gecko false --quiet"},
you can still run the project by using npm start
you can still build the project by using npm run build