@dojo/cli-build-widget

The official CLI command for building Dojo custom elements and widget libraries.

Usage
Features
How do I contribute?
- Installation
- Testing
Licensing information

Usage

To use @dojo/cli-build-widget in a single project, install the package:

npm install @dojo/cli-build-widget

Features

@dojo/cli-build-widget is an optional command for the @dojo/cli.

By default widgets are built using an evergreen configuration, meaning that the build process:

Prefers .mjs modules over .js modules
Uses { target: 'es6', module: 'esnext' } Typescript compiler options
Elides features based on the chrome flag from dojo/webpack-contrib

Project Structure

A custom elements or library project is expected to have the following directory and file structure:

src/
	custom-element-parent/
		customElementParent.m.css
		CustomElementParent.ts
	custom-element-child/
		customElementChild.m.css
		CustomElementChild.ts
tests/
	unit/
	functional/
.dojorc

Building

@dojo/cli-build-widget can be used to build either custom elements or a library of Dojo widgets. Library builds can be enabled with the --target=lib (or -t lib) flag. While custom element builds aim to provide a minimum set of files required to render an individual custom element in the browser, library builds simply 1) transpile TypeScript to .mjs and legacy .js files, 2) build, minimize, and generate .d.ts and .js files for CSS modules, 3) and copy font and image assets.

When building a Dojo widgets library, any widget that should be included MUST be specified in the --widgets option (see both Widgets and Configuration below). When present, src/main.ts takes precedence.

There are two modes available to build Dojo custom elements or widget libraries: dist and dev. When building custom elements, a test mode is also provided. The mode required can be passed using the --mode flag:

# For custom element builds
dojo build --mode dist

# For library builds
dojo build --mode dist --target lib

The built files are written to the output/{mode selected} directory. The output mirrors the src directory, so if a custom element is located at src/custom-element/CustomElement.s, the built element will be output to output/{mode}/custom-element/CustomElement.js.

Note: dist is the default mode and so can be run without any arguments, dojo build.

Dist Mode

The dist mode creates a production ready build.

Dev mode

The dev mode creates a build that has been optimized for debugging and development.

Test mode

The test mode creates bundles that can be used to run the unit and functional tests for the custom element(s).

Serving An Example Page

A web server can be started with the --serve flag. By default, the build is served on port 9999, but this can be changed with the --port (-p) flag:

# build once and then serve on port 3000
dojo build -s -p 3000

Watching

Building with the --watch option observes the file system for changes, and recompiles to the appropriate output/{dist|dev|test} directory, depending on the current --mode. When used in the conjunction with the --serve option and --mode=dev, --watch=memory can be specified to enable automatic browser updates and hot module replacement (HMR).

dojo build -w # start a file-based watch
dojo build -s -w=memory -m=dev # build to an in-memory file system with HMR

Widgets

The path for widgets to build can be provided using the repeating option --widgets:

dojo build --widgets src/custom-element-child/CustomElementChild --widgets src/custom-element-parent/CustomElementParent

Legacy

To build widgets for legacy environments use the --legacy or -l flag. Widgets built with the legacy flag will need to include the polyfill for the native shim. For library builds, both legacy and evergreen JavaScript files are output side-by-side.

Eject

Ejecting @dojo/cli-build-widget will produce the following files under the config/build-widget directory:

build-options.json: the build-specific config options removed from the .dojorc
ejected.config.js: the root webpack config that passes the build options to the appropriate mode-specific config based on the --env.mode flag's value.
base.config.js: a common configuration used by the mode-specific configs.
dev.config.js: the configuration used during development.
dist.config.js: the production configuration.
test.config.js: the configuration used when running tests.
template/custom-element.js: A template that registers custom elements

As already noted, the dojorc's build-widget options are moved to config/build-widget/build-options.json after ejecting. Further, the modes are specified using webpack's env flag (e.g., --env.mode=dev), defaulting to dist. You can run a build using webpack with:

node_modules/.bin/webpack --config=config/build-widget/ejected.config.js --env.mode={dev|dist|test}

Configuration

Custom element/widget library projects use a .dojorc file at the project root to control various aspects of development such as testing and building. This file is required to build the project, it MUST be valid JSON, and for widget projects it MUST provide at least a widgets array with the widget paths. All other values are options. The following options can be used beneath the "build-widget" key:

`widgets`: string[]

Contains paths relative to the project root to the widgets that should be built.

{
	"build-widget": {
		"widgets": [
			"src/menu-item/MenuItem",
			"src/menu/Menu"
		]
	}
}

`bundles`: object

Useful for breaking a build into smaller bundles, the bundles option is a map of webpack bundle names to arrays of modules that should be bundled together. For example, with the following configuration both src/Foo and src/Bar will be grouped in the foo.[hash].js bundle:

{
	"build-widget": {
		"bundles": {
			"foo": [
				"src/Foo",
				"src/Bar"
			]
		}
	}
}

`features`: object

A map of has features to boolean flags that can be used when building in dist mode to remove unneeded imports or conditional branches. See the static-build-loader documentation for more information.

How do I contribute?

We appreciate your interest! Please see the Dojo Meta Repository for the Contributing Guidelines. This repository uses prettier for code style and is configured with a pre-commit hook to automatically fix formatting issues on staged .ts files before performing the commit.

Installation

To start working with this package, clone the repository and run:

npm install

In order to build the project, you can run all the build steps via:

npm run build

Scripts

watch

Will run a watcher process which looks for changes in the source code TypeScript files and runs the build scripts to update the contents of the built files in dist with latest changes made.

clean

Runs the clean up script which removes any built files like output, dist, coverage which get created on build and testing steps.

lint

Runs the ts-lint and prettier on all .ts files in the src and tests directories. ts-lint will ensure that all linting rules have been abided by and prettier will fix any detected code style violations in the code.

Testing

Test cases MUST be written using Intern using the BDD test interface and Assert assertion interface.

90% branch coverage MUST be provided for all code submitted to this repository, as reported by istanbul’s combined coverage results for all supported platforms.

The command is tested by running via the Dojo CLI and asserting the build output against known fixtures. To do this, a test artifact needs to be built and installed into the test-app:

npm test

Testing

Test cases MUST be written using Intern using the BDD test interface and Assert assertion interface.

90% branch coverage MUST be provided for all code submitted to this repository, as reported by istanbul’s combined coverage results for all supported platforms.

The command is tested by running via the Dojo CLI and asserting the build output against known fixtures. To do this, a test artifact needs to be built and installed into the test-app:

npm test

Once the test artifact has been installed, if there have been no changes to the command code grunt test can be used to repeat the tests.