[twitter-bootstrap] Angular 4: How to include Bootstrap?

In Angular4 as you deal with @types system, you should do following things,

Do,

1) npm install --save @types/jquery
2) npm install --save @types/bootstrap

tsconfig.json

look for types array and add jquery and bootstrap entries,

"types": [
      "jquery",
      "bootstrap",  
      "node"
]

Index.html

in head section add following entries,

  <link href="node_modules/bootstrap/dist/css/bootstrap.min.css" rel="stylesheet">
  <script src="node_modules/jquery/dist/jquery.min.js "></script>
  <script src="node_modules/bootstrap/dist/js/bootstrap.js "></script>

And start using jquery and bootstrap both.