Creating a Custom UI5 Web Components Package

This tutorial explains how to:

• Create an NPM package for your own UI5 Web Components.
• Use UI5 Web Components' standard build tools: @ui5/webcomponents-tools.
• Gain all @ui5/webcomponents capabilities such as HBS template support, i18n, theming, test setup, etc.

Note: Whether you use npm or yarn is a matter of preference.

Step 1. Create an NPM package.

Run the init command.

Note: The following command will create a new directory and initialize your package there. Make sure you haven't created a directory yourself.

• With npm:

  npm init @ui5/webcomponents-package

  or

  npm init @ui5/webcomponents-package <NEW-PACKAGE-NAME>

• With yarn:

  yarn create @ui5/webcomponents-package

  or

  yarn create @ui5/webcomponents-package <NEW-PACKAGE-NAME>

where <NEW-PACKAGE-NAME> is the name of your new package (and the name of the directory to be created), for example:

npm init @ui5/webcomponents-package my-components

will create a my-components directory and initialize the package there.

Follow the prompts.

The initialization script will ask you to choose:

• The name of your package (if you did not already pass a name when running the command above);
• The port for your dev server (8080 by default - just press Enter to select this);
• The tag of the sample web component that will be created (my-first-component by default - just press Enter to select this).

Your package is ready!

Just follow the instructions:

• cd <NEW-PACKAGE-NAME>
• npm i (or yarn if you prefer)
• npm start (or yarn start if you prefer)

Step 2. Run the dev server and test the build.

To run the dev server, as instructed above:

npm run start

or

yarn start

and once the project is built for the first time, the browser will automatically open the dev server URL.

You can also run the tests:

npm run test

or

yarn test

and the production build:

npm run build

or

yarn build.

Note: In order to run the tests for the first time, you must have built the project with either start or build.

That's it!

Understanding the Project Structure

package.json

The initialization script will add several packages as dependencies. These three @ui5/ packages will serve as the foundation of your own package and Web Components.

Package	Type of Dependency	Description
@ui5/webcomponents-base	dependency	Base classes and framework
@ui5/webcomponents-theming	dependency	Base theming assets
@ui5/webcomponents-tools	devDependency	Build tools and configuration assets

The initialization script will create several NPM scripts for you in package.json.

Task	Purpose
clean	Delete the dist/ directory with the build output.
build	Production build to the dist/ directory.
lint	Run a static code scan with eslint.
start	Build the project for development, run the dev server and watch for changes.
watch	Watch for changes only.
serve	Run the dev server only.
test	Run the dev server and execute the specs from the test/specs/ directory.
create-ui5-element	Create an empty Web Component with the given name.

Files in the main directory

The initialization script will create several files in your package's main directory.

File	Purpose
.eslintignore	Excludes the dist/ and test/ directories from static code scans.
package-scripts.js	An nps package scripts configuration file.
bundle.js	Entry point for the bundle used for development and tests.

You'll likely only need to change bundle.js to import your new components there.

The config/ directory

The config/ directory serves as a central place for most build and test tools configuration assets. Normally, you don't need to change any files there.

Custom configuration

The files in the config/ directory simply import UI5 Web Components default configuration for all tasks: rollup, wdio, eslint, etc.

If you need to customize any configuration, simply put your own content into the respective file in config/.

Examples:

• Modifying eslint settings.

  Open config/.eslintrc.js. It should look like this:

  module.exports = require("@ui5/webcomponents-tools/components-package/eslint.js");

  As you can see, this is just a proxy to UI5 Web Components default configuration. Put your own content instead:

  module.exports = {
  	"env": {
  		"browser": true,
  		"es6": true
  	},
  	"root": true,
  	"extends": "airbnb-base",
  	.............
  }

• Modifying wdio settings.

  Open config/wdio.conf.js. It should look like this:

  module.exports = require("@ui5/webcomponents-tools/components-package/wdio.js");

  Again, this is a proxy to UI5 Web Components default configuration.

  You could just paste the content of @ui5/webcomponents-tools/components-package/wdio.js here and modify at will.

  However, let's not replace the whole file by hand this time, but just modify the exported configuration object.

  const result = require("@ui5/webcomponents-tools/components-package/wdio.js");
  result.config.capabilities[0]["goog:chromeOptions"].args = ['--disable-gpu']; // From: ['--disable-gpu', '--headless']
  module.exports = result;

  In this example, what we did was simply replace one option in the configuration object to disable headless mode so that we can use browser.debug() in our *.spec.js files. For more on testing, see Testing Web Components.

The src/ directory

This is where you'll do most of the development. Let's see the necessary files for a my-first-component component.

Class and template files

The main files describing a Web Component are:

File	Purpose
src/MyFirstComponent.js	Web Component class
src/MyFirstComponent.hbs	Handlebars template

In order to understand how a UI5 Web Component works and what lies behind these two files, make sure you check the Developing Web Components section of the documentation.

For the purposes of this tutorial, however, you don't need to understand their internals, as they are automatically generated by the script and are in a working state already.

Theming-related files

A single set of CSS rules will be used for all themes. The only difference between themes may be the values of CSS Variables. Some CSS Vars, such as --sapBackgroundColor and --sapTextColor are standard and automatically managed by the framework. In addition, you can define your own CSS Vars and provide different values for them for the different themes. Set these CSS Vars in the parameters-bundle.css file for each theme. These files are the entry points for the styles build script.

File	Purpose
src/themes/MyFirstComponent.css	All CSS rules for the Web Component, same for all themes; will be inserted in the shadow root.
src/themes/sap_horizon/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_horizon theme
src/themes/sap_horizon_dark/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_horizon_dark theme
src/themes/sap_horizon_hcb/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_horizon_hcb theme
src/themes/sap_horizon_hcw/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_horizon_hcw theme
src/themes/sap_fiori_3/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_fiori_3 theme
src/themes/sap_fiori_3_dark/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_fiori_3_dark theme
src/themes/sap_fiori_3_hcb/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_fiori_3_hcb theme
src/themes/sap_fiori_3_hcw/parameters-bundle.css	Values for the component-specific CSS Vars for the sap_fiori_3_hcw theme

Note: It's up to you whether to put the CSS Vars directly in the parameters-bundle.css files for the different themes or to import them from separate .css files. You could have, for example, a MyFirstComponent-params.css file for each theme and import it into the parameters-bundle.css file: @import "MyFirstComponent-params.css";.

Again, to know more about how these files work, you could have a look at the Developing Web Components section of the documentation.

i18n files

You can define translatable texts as key-value pairs, separated by = in the messagebundle.properties file. Then you can provide translations for as many languages as needed.

File	Purpose
src/i18n/messagebundle.properties	Source file for all translatable texts
src/i18n/messagebundle_de.properties	Translations in German
src/i18n/messagebundle_en.properties	Translations in English
etc.	etc.

Let's have a look at the sample messagebundle.properties file, generated by the script.

#please wait text for the sample component
PLEASE_WAIT=wait

Here's where you define all i18n texts, optionally with comments for the translators (# Comment).

And now let's have a look at a sample file with translations, for example messagebundle_es.properties:

PLEASE_WAIT=Espere

Assets (additional themes, i18n texts, etc.)

File	Purpose
src/Assets.js	Entry point for your package assets.

This module imports all base assets (such as CLDR and the base theme parameters), but also your own package assets (i18n and package-specific theme parameters). Users of your package will have to import this module in their production applications in order to get additional themes support and i18n support.

Note: For easier development and testing, Assets.js is also imported in the dev/test bundle bundle.esm.js by the initialization script.

The test/ directory

File	Purpose
test/pages/*	Simple .html pages used for development and tests.
src/specs/*	Test specs, based on WDIO. They use the test pages for setup.

You can execute all specs by running yarn test or npm run test.

For more on testing, see our Testing Web Components section.

Public Consumption of Your Custom UI5 Web Components Package

Once you've developed your package and published it to NPM, application developers can import from the dist/ directory of your package any of your Web Components, and optionally the Assets.js module, if they want additional themes and i18n.

For example, if your package is called my-ui5-webcomponents, users will install it by:

npm i my-ui5-webcomponents --save

and then use it by:

import "my-ui5-webcomponents/Assets.js"; // optional
import "my-ui5-webcomponents/dist/MyFirstComponent.js"; // for my-first-component from this tutorial
import "my-ui5-webcomponents/dist/SomeOtherComponent.js";
import "my-ui5-webcomponents/dist/YetAnotherComponent.js";