using bootstrap angular 8 code example

Example 1: install bootstrap angular 9

From angular cli:

npm install --save bootstrap
npm install --save jquery

Then add the following paths to angular.json:

"node_modules/bootstrap/dist/css/bootstrap.css" in the projects -> architect -> build -> styles array
"node_modules/jquery/dist/jquery.js" in the projects -> architect -> build -> scripts array
"node_modules/bootstrap/dist/js/bootstrap.js" in the projects -> architect -> build -> scripts array

Example 2: install bootstrap in angular 9

npm install bootstrap --save