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Version: v4.40

Getting Started

Starting a New Project​

Prerequisites​

Stencil requires a recent LTS version of NodeJS and npm/yarn. Make sure you've installed and/or updated Node before continuing.

Running the create-stencil CLI​

The create-stencil CLI can be used to scaffold a new Stencil project, and can be run using the following command:

 npm init stencil

Stencil can be used to create standalone components, or entire apps. create-stencil, will provide a prompt so that you can choose the type of project to start:

? Select a starter project.

Starters marked as [community] are developed by the Stencil
Community, rather than Ionic. For more information on the 
Stencil Community, please see github.com/stencil-community

❯   component                Collection of web components that can be
                             used anywhere
    app [community]          Minimal starter for building a Stencil 
                             app or website
    ionic-pwa [community]    Ionic PWA starter with tabs layout and routes

Selecting the 'component' option will prompt you for the name of your project. Here, we'll name our project 'my-first-stencil-project':

✔ Pick a starter › component
? Project name › my-first-stencil-project

After hitting ENTER to confirm your choices, the CLI will scaffold a Stencil project for us in a directory that matches the provided project name. Upon successfully creating our project, the CLI will print something similar to the following to the console:

✔ Project name › my-first-stencil-project
✔ A new git repo was initialized
✔ All setup  in 26 ms

  We suggest that you begin by typing:

  $ cd my-first-stencil-project
  $ npm install
  $ npm start

  $ npm start
    Starts the development server.

  $ npm run build
    Builds your project in production mode.

  $ npm test
    Starts the test runner.

  Further reading:

   - https://github.com/ionic-team/stencil-component-starter

  Happy coding! 🎈

The first section describes a few commands required to finish getting your project bootstrapped.

cd my-first-stencil-project
npm install
npm start

This will change your current directory to my-first-stencil-project, install your dependencies for you, and start the development server.

Useful Initial Commands​

The second section of the create-stencil output describes a few useful commands available during the development process:

  • npm start starts a local development server. The development server will open a new browser tab containing your project's components. The dev-server uses hot-module reloading to update your components in the browser as you modify them for a rapid feedback cycle.

  • npm run build creates a production-ready version of your components. The components generated in this step are not meant to be used in the local development server, but rather within a project that consumes your components.

  • npm test runs your project's tests. The create-stencil CLI has created both end-to-end and unit tests when scaffolding your project.

Source Control​

As of create-stencil v3.3.0, a new git repository will be automatically created for you when you initialize a project if:

  1. git is installed
  2. Your project is not created under another git work tree (e.g. if you create a new project in a monorepo, a new git repo will not be created)

Versions of create-stencil prior to v3.3.0 do not interact with any version control systems (VCS). If you wish to place your project under version control, we recommend initializing your VCS now. If you wish to use git, run the following after changing your current directory to the root of your Stencil project:

$ git init
$ git add -A
$ git commit -m "initialize project using stencil cli"

My First Component​

Stencil components are created by adding a new file with a .tsx extension, such as my-component.tsx. The .tsx extension is required since Stencil components are built using JSX and TypeScript.

When we ran create-stencil above, it generated a component, my-component.tsx, that can be found in the src/components/my-component directory:

my-component.tsx
import { Component, Prop, h } from '@stencil/core';
import { format } from '../../utils/utils';

@Component({
  tag: 'my-component',
  styleUrl: 'my-component.css',
  shadow: true,
})
export class MyComponent {
  @Prop() first: string;
  @Prop() middle: string;
  @Prop() last: string;

  private getText(): string {
    return format(this.first, this.middle, this.last);
  }

  render() {
    return <div>Hello, World! I'm {this.getText()}</div>;
  }
}

Once compiled, this component can be used in HTML just like any other tag.

<my-component first="Stencil" middle="'Don't call me a framework'" last="JS"></my-component>

When rendered, the browser will display Hello World! I'm Stencil 'Don't call me a framework' JS.

Anatomy of my-component​

Let's dive in and describe what's happening in my-component, line-by-line.

After the import statements, the first piece we see is the @Component decorator:

@Component({
  tag: 'my-component',
  styleUrl: 'my-component.css',
  shadow: true,
})

This decorator provides metadata about our component to the Stencil compiler. Information, such as the custom element name (tag) to use, can be set here. This decorator tells Stencil to: