Libetia A

Libetia A


Using Web Components in Angular

This tutorial teaches you how to use and interact with web components in an Angular application. We’ll build a small UI that adds people to a data grid.

The base application

We are using the Angular CLI to generate a new project.

$ ng new webcomponents
$ cd webcomponents

Install components

The first step in using web components is installing them. In this case, we install vaadin-text-fieldvaadin-button, and vaadin-grid from the Vaadin component set.

$ npm install --save @vaadin/vaadin-text-field @vaadin/vaadin-button @vaadin/vaadin-grid

Web Components are most often distributed as JavaScript. Add the following option to the root tsconfig.json:


  compilerOptions: {
    "allowJs": true

Enable custom elements

By default, Angular assumes that all custom HTML elements are Angular components and throws errors when encountering non-angular components. You can enable custom elements by adding the CUSTOM_ELEMENTS_SCHEMA to the application module. At the same time, import the ReactiveFormsModule that we use for creating the form.


import { BrowserModule } from '@angular/platform-browser';
-import { NgModule } from '@angular/core';
+import { NgModule, CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';
+ import { ReactiveFormsModule } from '@angular/forms';

import { AppComponent } from './app.component';

  declarations: [AppComponent],

imports: [BrowserModule],

imports: [BrowserModule, ReactiveFormsModule],

providers: [],
bootstrap: [AppComponent]
export class AppModule {}

Add polyfills for older browsers

Although most modern browsers ship with built-in support for Web Components, there are still users out there with older browsers. If you want to make your app available to them as well, you want to include polyfills that emulate the functionality in browsers without native support.

The webcomponents.js polyfill comes with a loader script that can be used to load only the polyfills a particular browser needs. It loads the polyfills dynamically, so it cannot be imported directly as a JS dependency that gets built by Webpack. Instead, you need to copy over the dependencies and include the loader in your index file. The library also includes an ES5 compatibility script in case you transpile your app into ES5.

$ npm install --save-dev @webcomponents/webcomponentsjs

Copy polyfills

You need to copy over the polyfills to load them. You can do this by adding them to the assets array in angular.json.


"assets": [


"glob": "*/.js",

"input": +"node_modules/@webcomponents/webcomponentsjs",

"output": "webcomponents/"


Load polyfills

Then, include the loader and an optional import for the ES5 compatibility script in the <head> section of index.html.


<script src="webcomponents/webcomponents-loader.js"></script>
 if (!window.customElements{document.write('<!--');}

Verify that you can run the application with

$ ng serve

Building the application

You are now ready to use web components. Begin by importing the components in app.component.ts. At the same time, import FormGroup and FormControl for building the form.


import '@vaadin/vaadin-button';
import '@vaadin/vaadin-grid';
import '@vaadin/vaadin-text-field';
import { FormGroup, FormControl } from '@angular/forms';

The form and grid bind to a Person object. Create a definition for it. You can either to it in a separate file and import it, or inline it in the app component file.


class Person {
 constructor(public firstName: string, public lastName: string) {}

Finally, replace the component implementation with the following:


export class AppComponent {
 people: Person[] = []; (1)
 form = new FormGroup({ (2)
   firstName: new FormControl(''),
   lastName: new FormControl('')

 addPerson() { (3)
   this.people = [

 new Person(this.form.value.firstName, this.form.value.lastName)

  1. Our component state is an array of people that should be listed in the grid
  2. A reactive FormGroup with controls for firstName and lastName
  3. When submitting the form, create a new array containing a Person object with the information in the form, then reset the form.

Defining the view HTML

Replace the contents of the component HTML file with the following:


<form [formGroup]="form" (ngSubmit)="addPerson()"> (1)
   label="First Name"
   ngDefaultControl> (2)
   label="Last Name"
 <vaadin-button (click)="addPerson()"> Add </vaadin-button>

<vaadin-grid [items]="people"> (3)
  <vaadin-grid-column path="firstName" header="First name">
  <vaadin-grid-column path="lastName" header="Last name"> </vaadin-grid-column>
  1. Bind the formGroup to the one we defined in the component, submit to the addPerson method.
  2. In addition to formControlName, add ngDefaultControl.
  3. Bind the people array to the items property on the grid.

The only difference to a standard Angular form is the use of ngDefaultControl on the fields to tell Angular to treat the custom fields as standard text inputs.


Once you have installed polyfills for older browsers, you can use Web Components interchangeably with Angular components. For the most part, you would use Web Components as leaf node components, and Angular for views and other composite components.

Thanks for reading. If you liked this post, share it with all of your programming buddies!

Originally published on

#angular #angular-js #web-development

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Using Web Components in Angular

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Roberta  Ward

Roberta Ward


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Christa  Stehr

Christa Stehr


Install Angular - Angular Environment Setup Process

Angular is a TypeScript based framework that works in synchronization with HTML, CSS, and JavaScript. To work with angular, domain knowledge of these 3 is required.

  1. Installing Node.js and npm
  2. Installing Angular CLI
  3. Creating workspace
  4. Deploying your First App

In this article, you will get to know about the Angular Environment setup process. After reading this article, you will be able to install, setup, create, and launch your own application in Angular. So let’s start!!!

Angular environment setup

Install Angular in Easy Steps

For Installing Angular on your Machine, there are 2 prerequisites:

  • Node.js
  • npm Package Manager

First you need to have Node.js installed as Angular require current, active LTS or maintenance LTS version of Node.js

Download and Install Node.js version suitable for your machine’s operating system.

Npm Package Manager

Angular, Angular CLI and Angular applications are dependent on npm packages. By installing Node.js, you have automatically installed the npm Package manager which will be the base for installing angular in your system. To check the presence of npm client and Angular version check of npm client, run this command:

  1. npm -v

Installing Angular CLI

  • Open Terminal/Command Prompt
  • To install Angular CLI, run the below command:
  1. npm install -g @angular/cli

installing angular CLI

· After executing the command, Angular CLI will get installed within some time. You can check it using the following command

  1. ng --version

Workspace Creation

Now as your Angular CLI is installed, you need to create a workspace to work upon your application. Methods for it are:

  • Using CLI
  • Using Visual Studio Code
1. Using CLI

To create a workspace:

  • Navigate to the desired directory where you want to create your workspace using cd command in the Terminal/Command prompt
  • Then in the directory write this command on your terminal and provide the name of the app which you want to create. In my case I have mentioned DataFlair:
  1. Ng new YourAppName

create angular workspace

  • After running this command, it will prompt you to select from various options about the CSS and other functionalities.

angular CSS options

  • To leave everything to default, simply press the Enter or the Return key.

angular setup

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Angular Web Application Development

Angular framework is built using TypeScript language that helps to ensures higher security. Angular is the most preferred framework for building reactive single page web applications and creative components of the website.

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Component Interactions in Angular

Today, we are going to talk about Angular Component Communication, the last version of Angular is @9, but I will show definitions to communicate in all angular versions, probably it will be in the angular platform for a long time. If you need to start with basic concepts in Angular I recommend for you the tour of heroes before reading this article. Here

Angular is based on components, so if you start to create a page in angular you should split this page into small components, each component is a container for a small logic, HTML, and CSS when you have a lot of components you have a big problem called “Communication” How can I communicate with these components? Or what is the best way to communicate my components? In the next image here I’m showing some components and how you need to communicate with parents with children, siblings, child to parent, and more cases.

Ways To Communicate

  1. Input / Output
  2. Services
  3. ViewChild
  4. Event Bus Service
  5. State Management

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