Awesome

@dojo/webpack-contrib

This repository contains all of the custom Webpack plugins and loaders used by @dojo/cli-build-app and @dojo/cli-build-widget to facilitate building Dojo 2 applications and widgets, respectively.

• Usage
• Loaders
  • css-module-decorator-loader
  • css-module-dts-loader
  • promise-loader
  • static-build-loader
• Plugins
  • build-time-render
  • css-module-plugin
  • emit-all-plugin
  • external-loader-plugin
  • i18n-plugin
  • service-worker-plugin
  • webpack-bundle-analyzer
  • bootstrap-plugin
• Transformers
  • registry-transformer
  • element-transformer
• How do I contribute?
  • Code Style
  • Testing
• Licensing information

Usage

To use @dojo/webpack-contrib in a single project, install the package:

npm install @dojo/webpack-contrib

Loaders

css-module-decorator-loader

A webpack loader that injects CSS module path information into the generated modules, making it easier for @dojo/widget-core to resolve theme styles. This loader takes no options.

css-module-dts-loader

A webpack loader that generates .d.ts files for CSS modules. This is used by both @dojo/cli-build-app and @dojo/cli-build-widget to provide in-widget type checks for CSS classes.

The loader expects the following options:

Example:

const webpackConfig = {
	loaders: [
		// Generate `.d.ts` files for all CSS modules imported in TypeScript files beneath
		// the `src/` directory
		{
			include: './src/',
			test: /\.ts$/,
			enforce: 'pre',
			loader: '@dojo/webpack-contrib/css-module-dts-loader?type=ts&instanceName=APP_NAME'
		},
		// Generate `.d.ts` files for all CSS modules beneath the `src/` directory
		{
			include: './src/',
			test: /\.m\.css$/,
			enforce: 'pre',
			loader: '@dojo/webpack-contrib/css-module-dts-loader?type=css'
		}
	]
};

promise-loader

A webpack loader that returns a promise from require() calls that resolves to the requested resource. It also removes absolute paths from source maps, ensuring consistent builds across environments. It is used by @dojo/cli-build-app for lazily loading bundles.

This loader expects two parameters, one required and one optional:

1. The required promise implementation (e.g., bluebird). If there already exists a global Promise constructor, then global should be specified.
2. An optional chunk name.

Example:

const resourcePromise = require('@dojo/webpack-contrib/promise-loader?global,resource-chunk-name!./path/to/resource');
resourcePromise.then((resource) => {
	// resource is available
})

static-build-loader

A webpack loader which allows code to be statically optimized for a particular context at bundling time. This loader acts on JavaScript. Some examples show the TypeScript source, but the loader will only work if acting on the compiled output.

Features

The loader examines code, looking for usages of @dojo/has, @dojo/has.exists, @dojo/has.add, or has pragmas to optimize. It does this by parsing the AST structure of the code, and modifying it when appropriate.

The loader takes three options:

• features: A map of static features or a feature or list of features that resolve to a similar static map based on the functionality provided by the specified targets. Each key in the map is the name of the feature and the value is true if the feature is present in that context, otherwise false.
• isRunningInNode: An optional boolean parameter. If set to false this indicates that the loader will not be running in an environment with a Node-like require.
• staticOnly: A list of feature keys that should not have has.add calls modified. In most cases, this option will not be needed. It is provided for cases where a module will sometimes be parsed and have its flags resolved statically if so, but may also not be parsed and may require a different runtime value for the flag.

For example in a webpack configuration, the map of features would look like this:

{
    use: [
        {
            loader: '@dojo/webpack-contrib/static-build-loader',
            options: {
                features: {
                    'foo': true,
                    'bar': false
                },
                staticOnly: ['bar']
            }
        }
    ]
};

This asserts feature foo is true and feature bar is false. Alternatively a list of features can be provided that will be resolved to the appropriate map

{
	use: [
		{
			loader: '@dojo/webpack-contrib/static-build-loader',
			options: {
				features: [ 'firefox', 'chrome' ]
			}
		}
	]
}

Available features

When specifying a static map, any values can be used. When passing a string or list of strings, the following values are supported. Each value corresponds to the set of known features that the environment supports. If multiple features are specified, the intersection of available features will be returned.

• android
• chrome
• edge
• firefox
• ie11
• ios
• node
• node8
• safari

In either case, the resulting map is then used in the features below.

Dead Code Removal

The loader assumes that the @dojo/has API is being used in modules that are being compiled into a webpack bundle and attempts to rewrite calls to the has() API when it can see it has a statically asserted flag for that feature.

The loader detects structures like the following in transpiled TypeScript modules:

import has from './has';

if (has('foo')) {
    console.log('has foo');
}
else {
    console.log('doesn\'t have foo');
}

const bar = has('bar') ? 'has bar' : 'doesn\'t have bar';

And will rewrite the code (given the static feature set above), like:

import has from './has';

if (true) {
    console.log('has foo');
}
else {
    console.log('doesn\'t have foo');
}

const bar = false ? 'has bar' : 'doesn\'t have bar';

When this is minified via Uglify via webpack, Uglify looks for structures that can be optimised and would re-write it further to something like:

import has from './has';

console.log('has foo');

const bar = 'doesn\'t have bar';

Any features which are not statically asserted, are not re-written. This allows the code to determine at run-time if the feature is present.

Elided Imports

The loader looks for has pragmas, which are strings that contain a call to has for a specific feature, and removes the next import found in the code. For example, given the above feature set, which has foo = true and bar = false, the imports of 'a' and 'b' would be removed but 'c' and 'd' would remain.

"has('foo')";
const statementBeforeImport = 3;
// This is the next import so it will be removed despite
// the conetnet between it and the pragma
import 'a';
// The pragma can be negated to remove the import if the condition
// is known to be false
'!has("bar")';
import 'b';
'!has("foo")';
// This import will not be removed because `foo` is not false
import 'c';

'has("baz")';
// This import will not be removed because the value of `has('baz')`
// is now known statically
import 'd';

Plugins

build-time-render

A webpack plugin that generates a bundle's HTML and inlines critical CSS at build time. This is similar to server-side rendering, but does not require a dedicated server to manage it.

The plugin takes an options object with the following properties:

Usage

Beyond the plugin itself, it is also beneficial to include the @dojo/webpack-contrib/build-time-render/hasBuildTimeRender module in the entry config option. This file adds the has('build-item-render') flag that applications can use to determine whether the app has been pre-rendered.

The following example will generate an HTML file containing <script> tags for the specified entries, along with the critical CSS and HTML for the root, #account, and #help paths. Both the #faq and #contact hashes will display the #help HTML.

import BuildTimeRender from '@dojo/webpack-contrib/build-time-render/BuildTimeRender';

const entry = {
	main: {
		'@dojo/webpack-contrib/build-time-render/hasBuildTimeRender',
		'./src/main.ts',
		'./src/main.css'
	}
};

const webpackConfig = {
	entry,
	plugins: [
		new BuildTimeRender({
			entries: Object.keys(entry),
			paths: [
				'#account',
				{ path: '#help', match: [ 'faq', 'contact' ] }
			],
			root: 'app',
			useManifest: true
		})
	]
};

css-module-plugin

A webpack plugin that converts .m.css import paths to .m.css.js. This is used in conjunction with the css-module-dts-loader loader to ensure that webpack can probably resolve CSS module paths.

If the requested resource uses a relative path, then its path will be resolved relative to the requesting module. Otherwise, the resource will be loaded from ${basePath}node_modules (see below for the definition of basePath):

// Path is relative to the current module
import * as localCss from './path/to/local-styles.m.css';

// Imported from node_modules
import * as externalCss from 'some-mid/styles.m.css';

The plugin constructor accepts a single argument:

emit-all-plugin

Webpack is a bundler, which does not work well when build libraries. Rather than create separate toolchains for building libraries and applications/custom elements, the existing build tooling can be used to emit library files by way of the emitAllFactory that produces both a plugin instance and a custom TypeScript transformer. The transformer is needed to ensure that any .d.ts dependencies are correctly emitted, while the plugin ensures assets are emitted as individual files instead of as a generated bundle:

import { emitAllFactory } from '@dojo/webpack-contrib/emit-all-plugin/EmitAllPlugin';

// See list of available options below
const emitAll = emitAllFactory(options);

const config = {
	// ...
	plugins: [
		...,
		emitAll.plugin
	],
	module: {
		rules: [
			// ...
			{
				test: /.*\.ts(x)?$/,
				use: [
					{
						loader: 'ts-loader',
						options: {
							// ...
							getCustomTransformers(program) {
								return {
									before: [
										emitAll.transformer()
									]
								};
							}
						}
					}
				]
			}
		]
	}
}

At the very least CSS and transpiled TS files will be emitted, but additional assets can be included with a filter.

The factory takes an options object with the following properties:

external-loader-plugin

External libraries that cannot be loaded normally via webpack can be included in a webpack build using this plugin.

The plugin takes an options object with the following properties:

All external dependencies specified in the dependencies options will be placed in ${pathPrefix}/${outputPath}. Each ExternalDep in the dependencies array specifies one external dependency. Each can be a string, indicating a path that should be delegated to the configured loader, or an object with the following properties:

i18n-plugin

Rather than manually set locale data within an application's entry point, that data can instead be read from a config and injected in at build time.

The plugin accepts an options object with the following properties:

A custom module is generated from the locale data, injected into the bundle, and then imported into the specified entry point. The user's locale is compared against the default locale and supported locales, and if it is supported is set as the root locale for the application. If the user's locale is not supported, then the default locale is used. For example, the user's locale will be used in the following scenarios:

The user's locale can be represented by the default locale:

• Default Locale: 'en'
• Supported Locales: none
• User's locale: 'en-US'

The user's locale can be represented by one of the supported locales:

• Default Locale: 'en'
• Supported Locales: [ 'fr' ]
• User's locale: 'fr-CA'

However, in the following scenario the default locale will be used, although it still will be possible to switch between any of the supported locales at run time, since their required data will also be included in the build:

• Default Locale: 'en'
• Supported Locales: [ 'de', 'ja', 'ar' ]
• User's locale: 'cz'

service-worker-plugin

A custom webpack plugin that generates a service worker from configuration options, or simply ensures a custom service worker is copied to the output directory. Generated service workers support both precaching and runtime caching and allow you specify additional resources that should be loaded by the service worker.

The plugin accepts either a string path for an existing service worker to copy to the output directory, or an options object with the following properties:

Precaching

The precache option can take the following options to control precaching behavior:

Runtime Caching

In addition to precaching, strategies can be provided for specific routes to determine whether and how they can be cached. This routes option is an array of objects with the following properties:

Strategies

Four routing strategies are currently supported:

• networkFirst attempts to load a resource over the network, falling back on the cache if the request fails or times out. This is a useful strategy for assets that either change frequently or may change frequently (i.e., are not versioned).
• cacheFirst loads a resource from the cache unless it does not exist, in which case it is fetched over the network. This is best for resources that change infrequently or can be cached for a long time (e.g., versioned assets).
• networkOnly forces the resource to always be retrieved over the network, and is useful for requests that have no offline equivalent.
• staleWhileRevalidate requests resources from both the cache and the network simulaneously. The cache is updated with each successful network response. This strategy is best for resources that do not need to be continuously up-to-date, like user avatars. However, when fetching third-party resources that do not send CORS headers, it is not possible to read the contents of the response or verify the status code. As such, it is possible that a bad response could be cached. In such cases, the networkFirst strategy may be a better fit.

Example

import ServiceWorkerPlugin from '@dojo/webpack-contrib/service-worker-plugin/ServiceWorkerPlugin';

new ServiceWorkerPlugin({
	cachePrefix: 'my-app',

	// exclude the "admin" bundle from caching
	excludeBundles: [ 'admin' ],

	routes: [
		// Use the cache-first strategy for loading images, adding them to the "my-app-images" cache.
		// Only the first ten images should be cached, and for one week.
		{
			urlPattern: '.*\\.(png|jpg|gif|svg)',
			strategy: 'cacheFirst',
			cacheName: 'my-app-images',
			expiration: { maxEntries: 10, maxAgeSeconds: 604800 }
		},

		// Use the cache-first strategy to cache up to 25 articles that expire after one day.
		{
			urlPattern: 'http://my-app-url.com/api/articles',
			strategy: 'cacheFirst',
			expiration: { maxEntries: 25, maxAgeSeconds: 86400 }
		}
	]
});

webpack-bundle-analyzer

A webpack plugin that provides a visualization of the size of webpack output with an interactive sunburst graphic. Functionally this is a copy of webpack-bundle-analyzer with a custom visualization.

The plugin accepts an options object with the following optional properties.

Example

import BundleAnalyzerPlugin from '@dojo/webpack-contrib/webpack-bundle-analyzer/BundleAnalyzerPlugin';

new BundleAnalyzerPlugin({
	analyzerMode: 'static',
	reportFilename: '../info/report.html',
	openAnalyzer: false
});

bootstrap-plugin

A custom webpack plugin that conditionally loads supported dojo shims based on usage and browser capabilities.

Supported Shims

• @dojo/framework/shim/IntersectionObserver
• @dojo/framework/shim/ResizeObserver
• @dojo/framework/shim/WebAnimations

To use the plugin, use the provided bootstrap.js from @dojo/webpack-contrib/bootstrap-plugin as the application entry and add the plugin to the webpack configuration.

The BootstrapPlugin accepts requires the path to application entry point and an array of shimModules to process.

new BootstrapPlugin({
	entryPath: mainEntryPath,
	shimModules: [
		{
			module: '@dojo/framework/shim/IntersectionObserver',
			has: 'intersection-observer'
		},
		{
			module: '@dojo/framework/shim/ResizeObserver',
			has: 'resize-observer'
		},
		{
			module: '@dojo/framework/shim/WebAnimations',
			has: 'web-animations'
		}
	]
})

Transformers

registry-transformer

A custom TypeScript transformer that generates registry keys for widgets included in lazily-loaded bundles. This allows widget authors to use the same pattern for authoring widgets regardless of whether they are loaded from a registry or imported directly.

For example, if LazyWidget needs to be split into a separate bundle and this transformer is not applied, then LazyWidget would need to be added to the registry (registry.define('lazy-widget', LazyWidget)), and all calls to w(LazyWidget) would need to be updated to reference its registry key (w<LazyWidget>('lazy-widget')). By using this transformer, LazyWidget would instead be added to the registry at build time, allowing existing code to remain unchanged.

element-transformer

A custom TypeScript transformer that generates a custom element definition for specified widgets.

For example given a widget Hello,

import { v } from '@dojo/framework/widget-core/d';
import { WidgetBase } from '@dojo/framework/widget-core/WidgetBase';

interface HelloProperties {
	name: string;
	flag: boolean;
	onClick(): void;
	onChange(value: string): void;
}

export class Hello extends WidgetBase<HelloProperties> {
	protected render() {
		const { name } = this.properties;
		return v('h1', { }, [
			'Hello ${name}!'
		]);
	}
}

export default Hello;

The generated output would be ,

import { v } from '@dojo/framework/widget-core/d';
import { WidgetBase } from '@dojo/framework/widget-core/WidgetBase';

interface HelloProperties {
	name: string;
	flag: boolean;
	onClick(): void;
	onChange(value: string): void;
}

export class Hello extends WidgetBase<HelloProperties> {
	protected render() {
		const { name } = this.properties;
		return v('h1', { }, [
			'Hello ${name}!'
		]);
	}
}
Hello.__customElementDescriptor = { ...{ tagName: 'widget-hello', attributes: ['name'], properties: ['flag'], events: ['onClick', onChange'] }, ...Hello.prototype.__customElementDescriptor || {} };

export default Hello;

How do I contribute?

We appreciate your interest! Please see the Dojo 2 Meta Repository for the Contributing Guidelines.

Code Style

This repository uses prettier for code styling rules and formatting. A pre-commit hook is installed automatically and configured to run prettier against all staged files as per the configuration in the projects package.json.

An additional npm script to run prettier (with write set to true) against all src and test project files is available by running:

npm run prettier

Testing

To test this package, after ensuring all dependencies are installed (npm install), run the following command:

npm run test

Licensing information

© 2018 JS Foundation. New BSD license.