feat: add dedupe option

chore(package): update dependencies

chore(rollup): change require names

feat: add dedupe option

prevents bundling the same module multiple times by resolving it from the root node_modules

feat(rollup): add onwarn option to prevent this warnings

chore: change eslint settings for node files

style(node-test): fix lint warnings

style: fix lint warnings

test(rollup): warning messages

test: dedupe option

.eslintrc.js

@@ -28,13 +28,15 @@ module.exports = {
 			'blueprints/*/index.js',
 			'config/**/*.js',
 			'tests/dummy/config/**/*.js',
-			'node-tests/**/*.js'
+			'node-tests/**/*.js',
+			'lib/config/*.js'
 		],
 		excludedFiles: [
 			'addon/**',
 			'addon-test-support/**',
 			'app/**',
-			'tests/dummy/app/**'
+			'tests/dummy/app/**',
+			'tests/dummy/lib/**/node_modules/**'
 		],
 		parserOptions: {
 			sourceType: 'script',

README.md

@@ -120,6 +120,25 @@ import styles from './some-component.css';
 
 The imported files exports the styles in a template literal that can be interpolated in the component's template. The processed styles are transformed with Autoprefixer using the hosting app targets configured in `config/targets.js`.
 
+### `dedupe`
+
+type: `Array`   
+default: `[]`
+
+Module names that should be resolved from the app `node_modules` instead of another packages requiring them. This prevents bundling the same module multiple times.
+
+Example:
+
+```js
+'ember-cli-webcomponents-bundler': {
+  modules: true,
+  entrypointPaths: [
+    'lib/path-one'
+  ],
+  dedupe: ['lit-element', 'moment']
+}
+```
+
 ## Contribute
 
 If you want to contribute to this addon, please read the [CONTRIBUTING.md](CONTRIBUTING.md).

index.js

@@ -35,7 +35,8 @@ module.exports = {
 			modules: false,
 			entrypointPaths: [],
 			autoImport: true,
-			importStyles: false
+			importStyles: false,
+			dedupe: []
 		};
 
 		this.options = Object.assign(defaults, options);
@@ -132,6 +133,7 @@ module.exports = {
 					root: absEntrypointPath,
 					minify: this.options.minify,
 					outputfile: getOutputFileName(config),
+					dedupe: this.options.dedupe,
 					config
 				})
 			));

lib/config/babel.js

@@ -1,5 +1,3 @@
-/* eslint-env node */
-
 'use strict';
 
 const common = {

lib/config/output.js

@@ -1,5 +1,3 @@
-/* eslint-env node */
-
 'use strict';
 
 const babelConfig = require('./babel');

lib/config/rollup.js

@@ -1,12 +1,10 @@
-/* eslint-env node */
-
 'use strict';
 
 const babel = require('rollup-plugin-babel');
-const resolver = require('rollup-plugin-node-resolve');
-const commonjs = require('rollup-plugin-commonjs');
+const resolver = require('@rollup/plugin-node-resolve');
+const commonjs = require('@rollup/plugin-commonjs');
 const includePaths = require('rollup-plugin-includepaths');
-const multiEntry = require('rollup-plugin-multi-entry');
+const multiEntry = require('@rollup/plugin-multi-entry');
 const terser = require('rollup-plugin-terser').terser;
 const path = require('path');
 
@@ -15,6 +13,7 @@ module.exports = function({
 	outputfile,
 	root,
 	minify,
+	dedupe,
 	config
 }) {
 	const legacy = config.name === 'legacy';
@@ -25,6 +24,14 @@ module.exports = function({
 		entrypoint
 	].filter(Boolean);
 
+	const onwarn = (warning, next) => {
+		if (warning.code === 'THIS_IS_UNDEFINED') {
+			return;
+		}
+
+		next(warning);
+	};
+
 	return {
 		rollup: {
 			input: inputFiles,
@@ -35,12 +42,16 @@ module.exports = function({
 			},
 			plugins: [
 				commonjs(),
-				resolver(),
+				resolver({
+					browser: true,
+					dedupe
+				}),
 				multiEntry({ exports: false }),
 				includePaths({ paths: [root] }),
 				babel(config.babel),
 				minify && terser()
-			]
+			],
+			onwarn
 		}
 	};
 };

node-tests/integration/index-test.js

@@ -10,7 +10,9 @@ const MOCK_ENV_CONFIGS = {
 	default: path.resolve(__dirname, '../mocks/environment-default.js'),
 	modules: path.resolve(__dirname, '../mocks/environment-modules.js'),
 	noAutoImport: path.resolve(__dirname, '../mocks/environment-no-autoimport.js'),
-	noEntrypointPaths: path.resolve(__dirname, '../mocks/environment-no-entrypoints.js')
+	noEntrypointPaths: path.resolve(__dirname, '../mocks/environment-no-entrypoints.js'),
+	dedupe: path.resolve(__dirname, '../mocks/environment-dedupe.js'),
+	noDedupe: path.resolve(__dirname, '../mocks/environment-no-dedupe.js')
 };
 
 const emberCLIPath = path.resolve(__dirname, '../../node_modules/ember-cli/bin/ember');
@@ -24,11 +26,11 @@ function runEmberCommand(packagePath, command) {
 	return new Promise((resolve, reject) =>
 		exec(`${emberCLIPath} ${command}`, {
 			cwd: packagePath
-		}, (err, result) => {
+		}, (err, stdout, stderr) => {
 			if (err) {
 				reject(err);
 			}
-			resolve(result);
+			resolve({ stdout, stderr });
 		})
 	);
 }
@@ -57,6 +59,7 @@ describe('ember-cli-webcomponents-bundler | Integration | options', function() {
 
 		before(async() => {
 			await mockConfig(mockConfigFile);
+
 			return runEmberCommand(fixturePath, 'build --prod');
 		});
 
@@ -81,6 +84,7 @@ describe('ember-cli-webcomponents-bundler | Integration | options', function() {
 
 		before(async() => {
 			await mockConfig(mockConfigFile);
+
 			return runEmberCommand(fixturePath, 'build --prod');
 		});
 
@@ -105,6 +109,7 @@ describe('ember-cli-webcomponents-bundler | Integration | options', function() {
 
 		before(async() => {
 			await mockConfig(mockConfigFile);
+
 			return runEmberCommand(fixturePath, 'build --prod');
 		});
 
@@ -129,6 +134,7 @@ describe('ember-cli-webcomponents-bundler | Integration | options', function() {
 
 		before(async() => {
 			await mockConfig(mockConfigFile);
+
 			return runEmberCommand(fixturePath, 'build --prod');
 		});
 
@@ -143,4 +149,76 @@ describe('ember-cli-webcomponents-bundler | Integration | options', function() {
 			assert.noFileContent(vendorPath, 'window.customElements.forcePolyfill');
 		});
 	});
+
+	context('without dedupe (default)', () => {
+		const mockConfigFile = MOCK_ENV_CONFIGS.noDedupe;
+
+		before(async() => {
+			await mockConfig(mockConfigFile);
+
+			return runEmberCommand(fixturePath, 'build --prod');
+		});
+
+		after(async() => {
+			restoreConfig(mockConfigFile);
+			await fs.remove(distPath);
+		});
+
+		it('nested modules are not deduped', () => {
+			const bundlePath = outputFilePath('assets/dedupe/bundle.js');
+
+			assert.fileContent(bundlePath, 'nested weightless module');
+		});
+	});
+
+	context('with dedupe', () => {
+		const mockConfigFile = MOCK_ENV_CONFIGS.dedupe;
+
+		before(async() => {
+			await mockConfig(mockConfigFile);
+
+			return runEmberCommand(fixturePath, 'build --prod');
+		});
+
+		after(async() => {
+			restoreConfig(mockConfigFile);
+			await fs.remove(distPath);
+		});
+
+		it('does not include multiple instances of deduped modules', () => {
+			const bundlePath = outputFilePath('assets/dedupe/bundle.js');
+
+			assert.noFileContent(bundlePath, 'nested weightless module');
+		});
+	});
+});
+
+describe('ember-cli-webcomponents-bundler | Integration | CLI', function() {
+	this.timeout(TEST_TIMEOUT);
+
+	context('warning messages', () => {
+		const mockConfigFile = MOCK_ENV_CONFIGS.modules;
+		let output = {};
+
+		before(async() => {
+			await mockConfig(mockConfigFile);
+
+			output = await runEmberCommand(fixturePath, 'build --prod');
+
+			return output;
+		});
+
+		after(async() => {
+			restoreConfig(mockConfigFile);
+			await fs.remove(distPath);
+		});
+
+		it('does not log warnings about rewriting `this`', () => {
+			assert.equal(output.stderr.includes('`this` has been rewritten to `undefined`'), false);
+		});
+
+		it('logs another warnings', () => {
+			assert.ok(output.stderr.includes('could not be resolved'));
+		});
+	});
 });

node-tests/mocks/environment-dedupe.js

@@ -0,0 +1,27 @@
+'use strict';
+
+const path = require('path');
+const entrypoint = path.join('tests', 'dummy', 'lib');
+
+module.exports = function(environment) {
+	const ENV = {
+		modulePrefix: 'dummy',
+		environment,
+		rootURL: '/',
+		locationType: 'auto',
+		EmberENV: {
+			EXTEND_PROTOTYPES: {
+				Date: false
+			}
+		},
+		'ember-cli-webcomponents-bundler': {
+			modules: false,
+			entrypointPaths: [
+				path.join(entrypoint, 'dedupe')
+			],
+			dedupe: ['weightless']
+		}
+	};
+
+	return ENV;
+};

node-tests/mocks/environment-no-dedupe.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const path = require('path');
+const entrypoint = path.join('tests', 'dummy', 'lib');
+
+module.exports = function(environment) {
+	const ENV = {
+		modulePrefix: 'dummy',
+		environment,
+		rootURL: '/',
+		locationType: 'auto',
+		EmberENV: {
+			EXTEND_PROTOTYPES: {
+				Date: false
+			}
+		},
+		'ember-cli-webcomponents-bundler': {
+			modules: false,
+			entrypointPaths: [
+				path.join(entrypoint, 'dedupe')
+			]
+		}
+	};
+
+	return ENV;
+};