How to use Bootstrap 4 to style apps built using Angular 9

In this tutorial, we will see how to use Bootstrap to style apps built using Angular 9.

We’ll see how to integrate Angular with Bootstrap, in various ways including using ng-bootstrap and ngx-bootstrap packages.

We’ll be using Angular CLI 9 for generating a brand new project.

What is Bootstrap

Bootstrap is the most popular HTML and CSS framework for building responsive layouts with ease and without having a deep knowledge of CSS (Still custom CSS is required to customize your design ane make it different from the other Bootstrap-styled websites unless you are using a BS theme developed specifically for you).

Bootstrap 4 is the latest version of BS which brings many new and powerful features to the framework most importantly Flexbox which is now the default display system for BS grid layout (one of the most important features of BS).

3+ Ways to Include Bootstrap 4 In Your Angular Project

This can be done in multiple ways:

  • Including the Bootstrap CSS and JavaScript files in the <head> section of the index.html file of your Angular project with a <link> and <script> tags,

  • Importing the Bootstrap CSS file in the global styles.css file of your Angular project with an @import keyword.

  • Adding the Bootstrap CSS and JavaScript files in the styles and scripts arrays of the angular.json file of your project

Step 1 - Installing Angular CLI v9

Let’s get started by installing Angular CLI v9 if it is not yet installed on your machine.

Head over to a new command-line interface and run the following command to install the latest version of the Angular CLI:

$ npm install -g @angular/cli@next

At the time of writing this tutorial, Angular 9 is still in pre-release, so we need to use the next tag to install it. Angular v9.0.0-rc.2 is installed.

After the installation, you’ll have at your disposal the ng utility. Let’s use it to generate a new Angular 9 project.

$ ng new angular-bootstrap-examples

You will be prompted for a couple of questions:

? Would you like to add Angular routing? Yes
? Which stylesheet format would you like to use? (Use arrow keys)
  SCSS   [                ]
  Sass   [ ]
  Less   [                                             ]
  Stylus [                                         ]

Most importantly, choose CSS as the stylesheet format because we’ll use ths CSS version of Bootstrap in our tutorial.

The command will generate the directory structure and necessary files for the project and will install the required dependencies.

Next, navigate inside the root folder of your project

$ cd angular-bootstrap-examples

You can then serve your Angular 9 application using the ng serve command as follows:

$ ng serve

Your app will be served from http://localhost:4200/

Step 2 - Installing Bootstrap 4 in Your Angular 9 Project

In this step, we’ll proceed to add Bootstrap 4 to our Angular 9 application.

There are various ways that you can use to install Bootstrap in your project:

  • Installing Bootstrap from npm using the npm install command,
  • Downloading Bootstrap files and adding them to the src/assets folder of your Angular project,
  • Using Bootstrap from a CDN.

Let’s proceed with the first method. Go back to your command-line interface and install Bootstrap 4 via npm as follows:

 $ npm install --save bootstrap

This will also add the bootstrap package to package.json.

As the time of writing this tutorial, bootstrap v4.3.1 will be installed.

The Bootstrap 4 assets will be installed in the node_modules/bootstrap folder. You’ll need to tell Angular where to look for them.

Next, you also need to install jQuery using the following command:

 $ npm install --save jquery

At the time of this tutorial jquery v3.4.1 will be installed.

Step 3 (Method 1) - Adding Bootstrap 4 to Angular 9 Using angular.json

Open the angular.json file of your project and include:

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

As follows:

  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1, 
  "newProjectRoot": "projects",
  "projects": {
    "angular-bootstrap-examples": {
      "projectType": "application",
      "schematics": {},
      "root": "",
      "sourceRoot": "src",
      "prefix": "app",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/angular-bootstrap-examples",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "",
            "aot": true,
            "assets": [
            "styles": [
            "scripts": [

Note: You also need to add the jQuery JavaScript library file.

Step 3 (Method 2) - Adding Bootstrap 4 to Angular 9 Using index.html

You can also include Bootstrap files from node_modules/bootstrap using the index.html file.

Open the src/index.html file and add the following:

  • A <link> tag for adding the bootstrap.css file in the <head> section,
  • A <script> tag for adding the jquery.js file before the closing </body> tag,
  • A <script> tag for adding the bootstrap.js file before the </body> tag.
<!doctype html>
<html lang="en">
  <meta charset="utf-8">
  <title>Angular Bootstrap 4 Examples</title>
  <base href="/">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="icon" type="image/x-icon" href="favicon.ico">
  <link rel="stylesheet" href="../node_modules/bootstrap/dist/css/bootstrap.css">

  <script src="../node_modules/jquery/dist/jquery.js"></script>
  <script src="../node_modules/bootstrap/dist/js/bootstrap.js"></script>    

Step 3 (Method 3) - Adding Bootstrap 4 to Angular 9 Using styles.css

We can also use the styles.css file to add the CSS file of Bootstrap to our project.

Open the src/styles.css file of your Angular project and import the bootstrap.css file as follows:

@import "~bootstrap/dist/css/bootstrap.css"

This replaces the previous method(s) so you don’t need to add the file to the styles array of the angular.json file or to the index.html file.

Note: The JS file(s) can be added using the scripts array or the <script> tag as the previous methods.

“Adding_Bootstrap_4_Using_ng-bootstrap_and_ngx-bootstrap”>Alternative Step - Adding Bootstrap 4 Using ng-bootstrap and ngx-bootstrap

Bootstrap depends on jQuery and Popper.js libraries, and if you don’t include them in your project, any Bootstrap components that rely on JavaScript will not work.

Why not include those libs? For Angular it’s better to avoid using libraries that make direct manipulation of the DOM (like jQuery) and let Angular handle that.

Now what if you need the complete features of Bootstrap 4 without the JS libraries?

A better way is to use component libraries created for the sake of making Bootstrap work seamlessly with Angular such as ng-bootstrap or ngx-bootstrap

This is image title

Should I add bootstrap.js or bootstrap.min.js to my project? No, the goal of ng-bootstrap is to completely replace JavaScript implementation for components. Nor should you include other dependencies like jQuery or popper.js. It is not necessary and might interfere with ng-bootstrap code Source

So first you’ll need to install the library from npm using the following command:

npm install --save @ng-bootstrap/ng-bootstrap

Once you finish the installation you’ll need to import the main module.

import {NgbModule} from '@ng-bootstrap/ng-bootstrap';

Next you’ll need to add the module you imported in your app root module

import {NgbModule} from '@ng-bootstrap/ng-bootstrap';

  declarations: [/*...*/],
  imports: [/*...*/, NgbModule.forRoot()],
export class AppModule {

Please note that ng-bootstrap requires the Bootstrap 4 CSS file to be present.

You can add it in the styles array of the angular.json file like that:

"styles": [

Now you can use Bootstrap 4 in your Angular application.

You can find all the available components via this link.

You can also use the ngx-bootstrap library !

This is image title

Simply head back to your terminal, make sure you are inside your Angular project then run the following command to install ngx-bootstrap

npm install ngx-bootstrap --save

You also need the Bootstrap 4 CSS files. Add the following line in the <head> of your Angular app which includes Bootstrap from a CDN

<link href="" rel="stylesheet">

You can also install bootstrap from npm and use the previous way to include the CSS file (via the styles array in the angular-cli.json file)

   "styles": [  

Next open src/app/app.module.ts and add

import { BsDropdownModule} from 'ngx-bootstrap/dropdown';
import { AlertModule } from 'ngx-bootstrap';


   imports: [BsDropdownModule.forRoot(),AlertModule.forRoot(), /*...*/ ],

This an example of importing two components BsDropdownModule and AlertModule.

You need to import the module for each component you want to use in the same way.

ngx-bootstrap provides each BS component in each own module so you only import the components you need. In this way your app will be smaller since it bundles only the components you are actually using.

You can find all the available components that you can use from the docs

Adding Bootstrap 4 to Angular 9

Thanks to the new ng add command added on Angular 7+, you have a new simpler and easier way to add Bootstrap without using the npm install command for installing the required dependencies or adding any configurations.

You can simply run the following command to add ng-bootstrap:

$ ng add @ng-bootstrap/schematics

That’s it. You now have support for Bootstrap components and styles without any extra configurations. You also don’t need jQuery since we are using ng-bootstrap.


In this article, we’ve seen different ways of including Bootstrap 4 in Angular 9 apps:

  • Using original Bootstrap 4 assets from npm,
  • Using the ng-bootstrap library,
  • And finally using the ngx-bootstrap

The most important difference between ng-bootstrap vs. ngx-bootstrapis that ngx-bootstrap uses separate modules for components to reduce the final app size.

Thank you for reading!

#Angular #Bootstrap4 #CSS #Javascript

How to use Bootstrap 4 to style apps built using Angular 9
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