.npmrc

+save-exact = true

.prettierignore

@@ -2,15 +2,21 @@
 /package.json
 /package-lock.json
 
-# generated by renovatebot
-/.renovaterc.json
-
 # compiled files
 /build
 /coverage
+/public/**/*.html
 /public/assets
+/public/schemas
 /docs/**/__tests__/*.spec.ts
 
 # nunjucks templates
+/docs/**/*.html
 /docs/dgeni/inline-validate/templates
 /docs/dgeni/schema/templates
+
+# will contain errors
+/test-files/**/*.html
+
+# local test files
+/sites

CHANGELOG.md

 # html-validate changelog
 
+# [2.19.0](https://gitlab.com/html-validate/html-validate/compare/v2.18.1...v2.19.0) (2020-03-24)
+
+### Bug Fixes
+
+- **meta:** deep merge during inheritance ([85c377d](https://gitlab.com/html-validate/html-validate/commit/85c377d185492407d72fde39bd14d6a80935a56a)), closes [#72](https://gitlab.com/html-validate/html-validate/issues/72)
+
+### Features
+
+- **meta:** implicit inheritance when overriding existing element ([8833a0f](https://gitlab.com/html-validate/html-validate/commit/8833a0fcc9873eee4938619cdae78afa45e48ce5))
+
 ## [2.18.1](https://gitlab.com/html-validate/html-validate/compare/v2.18.0...v2.18.1) (2020-03-22)
 
 ### Bug Fixes

Gruntfile.js

 const sass = require("sass");
 const serveStatic = require("serve-static");
 
-module.exports = function(grunt) {
+module.exports = function (grunt) {
 	require("load-grunt-tasks")(grunt);
 
 	grunt.registerTask("default", ["build"]);
 
-	grunt.registerTask("dgeni", "Generate documentation", function() {
+	grunt.registerTask("dgeni", "Generate documentation", function () {
 		const Dgeni = require("dgeni");
 		const done = this.async();
 		const dgeni = new Dgeni([require("./docs/dgeni")]);
@@ -97,7 +97,7 @@ module.exports = function(grunt) {
 				hostname: "localhost",
 				keepalive: true,
 				base: "public",
-				middleware: function() {
+				middleware: function () {
 					return [serveStatic("public")];
 				},
 			},

docs/dgeni/bootstrap/index.js

@@ -2,7 +2,7 @@ const Package = require("dgeni").Package;
 
 const pkg = new Package("dgeni-bootstrap", []);
 
-pkg.config(function(inlineTagProcessor, getInjectables) {
+pkg.config(function (inlineTagProcessor, getInjectables) {
 	const inlineTagsDefs = getInjectables(require("./inline-tag-defs"));
 	inlineTagProcessor.inlineTagDefinitions = inlineTagProcessor.inlineTagDefinitions.concat(
 		inlineTagsDefs

docs/dgeni/bootstrap/inline-tag-defs/alert-danger.js

@@ -2,7 +2,7 @@ module.exports = function alertDangerInlineTagDef() {
 	return {
 		name: "alert-danger",
 		description: "Add bootstrap danger alert",
-		handler: function(doc, tagName, tagDescription) {
+		handler: function (doc, tagName, tagDescription) {
 			return `<div class="alert alert-danger"><i class="fa fa-exclamation-triangle" aria-hidden="true"></i> ${tagDescription}</div>`;
 		},
 	};

docs/dgeni/bootstrap/inline-tag-defs/alert-info.js

@@ -2,7 +2,7 @@ module.exports = function alertInfoInlineTagDef() {
 	return {
 		name: "alert-info",
 		description: "Add bootstrap info alert",
-		handler: function(doc, tagName, tagDescription) {
+		handler: function (doc, tagName, tagDescription) {
 			return `<div class="alert alert-info"><i class="fa fa-info-circle" aria-hidden="true"></i> ${tagDescription}</div>`;
 		},
 	};

docs/dgeni/bootstrap/inline-tag-defs/alert-success.js

@@ -2,7 +2,7 @@ module.exports = function alertSucccessInlineTagDef() {
 	return {
 		name: "alert-success",
 		description: "Add bootstrap success alert",
-		handler: function(doc, tagName, tagDescription) {
+		handler: function (doc, tagName, tagDescription) {
 			return `<div class="alert alert-success"><i class="fa fa-check" aria-hidden="true"></i> ${tagDescription}</div>`;
 		},
 	};

docs/dgeni/bootstrap/inline-tag-defs/alert-warning.js

@@ -2,7 +2,7 @@ module.exports = function alertWarningInlineTagDef() {
 	return {
 		name: "alert-warning",
 		description: "Add bootstrap warning alert",
-		handler: function(doc, tagName, tagDescription) {
+		handler: function (doc, tagName, tagDescription) {
 			return `<div class="alert alert-warning"><i class="fa fa-exclamation-triangle" aria-hidden="true"></i> ${tagDescription}</div>`;
 		},
 	};

docs/dgeni/changelog.js

@@ -9,7 +9,7 @@ function prepare(src) {
 module.exports = function changelogFileReader() {
 	return {
 		name: "changelogFileReader",
-		getDocs: function(fileInfo) {
+		getDocs: function (fileInfo) {
 			return [
 				{
 					docType: "changelog",

docs/dgeni/filters/asset-hash.js

@@ -3,14 +3,11 @@ const crypto = require("crypto");
 
 module.exports = {
 	name: "assetHash",
-	process: asset => {
+	process: (asset) => {
 		const filename = `public/${asset}`;
 		if (fs.existsSync(filename)) {
 			const data = fs.readFileSync(filename);
-			const hash = crypto
-				.createHash("md5")
-				.update(data)
-				.digest("hex");
+			const hash = crypto.createHash("md5").update(data).digest("hex");
 			return `${asset}?${hash}`;
 		} else {
 			console.log(

docs/dgeni/highlight/index.js

@@ -9,11 +9,11 @@ module.exports = new Package("highlight", [require("dgeni-packages/nunjucks")])
 	.factory(require("./filters/highlight"))
 
 	/* enable syntax highlighting */
-	.config(function(renderMarkdown, highlight) {
+	.config(function (renderMarkdown, highlight) {
 		renderMarkdown.highlight = highlight;
 	})
 
 	/* add highlight filter */
-	.config(function(templateEngine, highlightFilter) {
+	.config(function (templateEngine, highlightFilter) {
 		templateEngine.filters.push(highlightFilter);
 	});

docs/dgeni/highlight/services/renderMarkdown.js

@@ -8,7 +8,7 @@ module.exports = function renderMarkdown(trimIndentation) {
 
 	// remove the leading whitespace from the code block before it gets to the
 	// markdown code render function
-	renderer.code = function(code, string, language) {
+	renderer.code = function (code, string, language) {
 		const trimmedCode = trimIndentation(code);
 		let renderedCode = marked.Renderer.prototype.code.call(
 			this,
@@ -38,7 +38,7 @@ module.exports = function renderMarkdown(trimIndentation) {
 	};
 
 	// Add § link to all headings
-	renderer.heading = function(text, level, raw) {
+	renderer.heading = function (text, level, raw) {
 		const slug = raw
 			.toLowerCase()
 			.replace(/\(.*?\)/g, "")
@@ -51,7 +51,7 @@ module.exports = function renderMarkdown(trimIndentation) {
 		return `<h${level} id="${id}">${text}${anchor}</h${level}>`;
 	};
 
-	const render = function(content) {
+	const render = function (content) {
 		return marked(content, {
 			highlight: render.highlight,
 			renderer,

docs/dgeni/index.js

@@ -13,13 +13,13 @@ module.exports = new Package("html-validate-docs", [
 
 	.processor(require("./processors/rules"))
 
-	.config(function(renderDocsProcessor) {
+	.config(function (renderDocsProcessor) {
 		renderDocsProcessor.extraData.pkg = require("../../package.json");
 		renderDocsProcessor.extraData.tracking = process.env.GA_TRACKING_ID;
 	})
 
 	/* configure markdown syntax highlighting */
-	.config(function(highlight) {
+	.config(function (highlight) {
 		highlight.configure({
 			languages: ["js", "json", "typescript", "html", "shell"],
 		});
@@ -27,15 +27,15 @@ module.exports = new Package("html-validate-docs", [
 
 	.factory(require("./changelog"))
 
-	.config(function(readFilesProcessor, changelogFileReader) {
+	.config(function (readFilesProcessor, changelogFileReader) {
 		readFilesProcessor.fileReaders.push(changelogFileReader);
 	})
 
-	.config(function(getLinkInfo) {
+	.config(function (getLinkInfo) {
 		getLinkInfo.relativeLinks = true;
 	})
 
-	.config(function(log, readFilesProcessor, writeFilesProcessor, copySchema) {
+	.config(function (log, readFilesProcessor, writeFilesProcessor, copySchema) {
 		log.level = "info";
 
 		readFilesProcessor.basePath = path.resolve(packagePath, "../..");
@@ -59,14 +59,14 @@ module.exports = new Package("html-validate-docs", [
 		writeFilesProcessor.outputFolder = "public";
 	})
 
-	.config(function(parseTagsProcessor, getInjectables) {
+	.config(function (parseTagsProcessor, getInjectables) {
 		parseTagsProcessor.tagDefinitions = parseTagsProcessor.tagDefinitions.concat(
 			getInjectables(require("./tag-defs"))
 		);
 	})
 
 	/* add custom nunjuck filters */
-	.config(function(templateEngine) {
+	.config(function (templateEngine) {
 		templateEngine.filters = templateEngine.filters.concat(
 			require("./filters")
 		);
@@ -74,16 +74,16 @@ module.exports = new Package("html-validate-docs", [
 
 	/* add the local template folder first in the search path so it overrides
 	 * dgeni-packages bundled templates */
-	.config(function(templateFinder) {
+	.config(function (templateFinder) {
 		templateFinder.templateFolders.unshift(
 			path.resolve(packagePath, "templates")
 		);
 	})
 
-	.config(function(computePathsProcessor, computeIdsProcessor) {
+	.config(function (computePathsProcessor, computeIdsProcessor) {
 		computeIdsProcessor.idTemplates.push({
 			docTypes: ["content", "frontpage", "rule", "rules", "changelog", "error"],
-			getId: function(doc) {
+			getId: function (doc) {
 				const dir = path.dirname(doc.fileInfo.relativePath);
 				if (dir === ".") {
 					/* documents not in a subdirectory gets basename as id */
@@ -98,7 +98,7 @@ module.exports = new Package("html-validate-docs", [
 					return dir;
 				}
 			},
-			getAliases: function(doc) {
+			getAliases: function (doc) {
 				const alias = [doc.id];
 				if (doc.name) {
 					alias.push(doc.name);
@@ -110,7 +110,7 @@ module.exports = new Package("html-validate-docs", [
 
 		computePathsProcessor.pathTemplates.push({
 			docTypes: ["content", "frontpage", "rule", "rules"],
-			getPath: function(doc) {
+			getPath: function (doc) {
 				const dirname = path.dirname(doc.fileInfo.relativePath);
 				const p = path.join(dirname, doc.fileInfo.baseName);
 				return `${p}.html`;
@@ -120,7 +120,7 @@ module.exports = new Package("html-validate-docs", [
 
 		computePathsProcessor.pathTemplates.push({
 			docTypes: ["changelog"],
-			getPath: function(doc) {
+			getPath: function (doc) {
 				const dirname = path.dirname(doc.fileInfo.relativePath);
 				return path.join(dirname, doc.fileInfo.baseName, "index.html");
 			},
@@ -129,7 +129,7 @@ module.exports = new Package("html-validate-docs", [
 
 		computePathsProcessor.pathTemplates.push({
 			docTypes: ["error"],
-			getPath: function(doc) {
+			getPath: function (doc) {
 				/* should go directly under output directory, no subdirectory */
 				return doc.fileInfo.baseName;
 			},
@@ -137,10 +137,10 @@ module.exports = new Package("html-validate-docs", [
 		});
 	})
 
-	.config(function(checkAnchorLinksProcessor) {
+	.config(function (checkAnchorLinksProcessor) {
 		checkAnchorLinksProcessor.ignoredLinks.push(/^\/$/);
 		checkAnchorLinksProcessor.ignoredLinks.push(/^\/changelog$/);
-		checkAnchorLinksProcessor.checkDoc = doc => {
+		checkAnchorLinksProcessor.checkDoc = (doc) => {
 			return (
 				doc.path &&
 				doc.outputPath &&

docs/dgeni/inline-validate/index.js

@@ -15,30 +15,30 @@ module.exports = new Package("inline-validate", [])
 	.factory(require("./services/validateMap"))
 	.factory(require("./inline-tag-defs/inline-validation"))
 
-	.config(function(templateFinder) {
+	.config(function (templateFinder) {
 		templateFinder.templateFolders.push(path.resolve(packagePath, "templates"));
 	})
 
-	.config(function(inlineTagProcessor, inlineValidationInlineTagDef) {
+	.config(function (inlineTagProcessor, inlineValidationInlineTagDef) {
 		inlineTagProcessor.inlineTagDefinitions.push(inlineValidationInlineTagDef);
 	})
 
-	.config(function(computePathsProcessor, computeIdsProcessor) {
+	.config(function (computePathsProcessor, computeIdsProcessor) {
 		computePathsProcessor.pathTemplates.push({
 			docTypes: ["validate-config", "validate-markup"],
-			getPath: function() {},
+			getPath: function () {},
 			outputPathTemplate: "inline-validations/${id}",
 		});
 		computePathsProcessor.pathTemplates.push({
 			docTypes: ["validate-spec"],
-			getPath: function() {},
+			getPath: function () {},
 			outputPathTemplate:
 				"../${fileInfo.path}/__tests__/${fileInfo.file}.spec.ts",
 		});
 		computePathsProcessor.pathTemplates.push({
 			docTypes: ["inlineValidation"],
 			pathTemplate: "inline-validations/${validate.id}",
-			getOutputPath: function() {},
+			getOutputPath: function () {},
 		});
 		computeIdsProcessor.idTemplates.push({
 			docTypes: [
@@ -47,7 +47,7 @@ module.exports = new Package("inline-validate", [])
 				"validate-spec",
 				"inlineValidation",
 			],
-			getAliases: function(doc) {
+			getAliases: function (doc) {
 				return [doc.id];
 			},
 		});

docs/dgeni/inline-validate/processors/validate-generate-spec.js

@@ -10,7 +10,7 @@ module.exports = function generateValidationsSpecProcessor(log, validateMap) {
 	function $process(docs) {
 		const specs = {};
 
-		validateMap.forEach(validation => {
+		validateMap.forEach((validation) => {
 			const key = validation.doc.fileInfo.relativePath;
 
 			if (!specs[key]) {

docs/dgeni/inline-validate/processors/validate-generate.js

@@ -6,7 +6,7 @@ module.exports = function generateInlineValidationsProcessor(log, validateMap) {
 	};
 
 	function $process(docs) {
-		validateMap.forEach(validation => {
+		validateMap.forEach((validation) => {
 			const inlineValidationDoc = createInlineValidateDoc(validation);
 			docs.push(inlineValidationDoc);
 			validation.inlineValidationDoc = inlineValidationDoc;

docs/dgeni/inline-validate/processors/validate-parse.js

@@ -16,7 +16,7 @@ module.exports = function parseValidatesProcessor(
 	};
 
 	function $process(docs) {
-		docs.forEach(doc => {
+		docs.forEach((doc) => {
 			try {
 				if (!doc.content) {
 					return;
@@ -73,7 +73,7 @@ module.exports = function parseValidatesProcessor(
 
 	function extractAttributes(attributeText) {
 		const attributes = {};
-		attributeText.replace(ATTRIBUTE_REGEX, function(match, prop, val1, val2) {
+		attributeText.replace(ATTRIBUTE_REGEX, function (match, prop, val1, val2) {
 			attributes[prop] = val1 || val2;
 		});
 		return attributes;

docs/dgeni/inline-validate/processors/validate-results.js

@@ -13,7 +13,7 @@ module.exports = function generateValidationResultsProcessor(log, validateMap) {
 	function $process() {
 		const oldLevel = chalk.level;
 		chalk.level = 0;
-		validateMap.forEach(validation => {
+		validateMap.forEach((validation) => {
 			htmlvalidate = new HtmlValidate(validation.config);
 			validation.report = htmlvalidate.validateString(validation.markup);
 			validation.codeframe = codeframe(validation.report.results);

docs/dgeni/processors/rules.js

@@ -27,7 +27,7 @@ module.exports = function rulesProcessor(renderDocsProcessor) {
 		const ruleDocs = docs.filter(isRuleDocument);
 
 		/* compule rule source paths */
-		ruleDocs.forEach(doc => {
+		ruleDocs.forEach((doc) => {
 			const docPath = doc.fileInfo.projectRelativePath;
 			doc.ruleSourcePath = docPath
 				.replace("docs", "src")
@@ -35,7 +35,7 @@ module.exports = function rulesProcessor(renderDocsProcessor) {
 		});
 
 		/* generate title */
-		ruleDocs.forEach(doc => {
+		ruleDocs.forEach((doc) => {
 			if (!doc.title) {
 				doc.title = `${doc.summary} (${doc.name})`;
 			}
@@ -43,7 +43,7 @@ module.exports = function rulesProcessor(renderDocsProcessor) {
 
 		/* find all available rules */
 		const rules = ruleDocs
-			.map(doc => ({
+			.map((doc) => ({
 				name: doc.name,
 				url: doc.outputPath,
 				category: doc.category,
@@ -55,7 +55,7 @@ module.exports = function rulesProcessor(renderDocsProcessor) {
 
 		/* group rules into categories */
 		const categories = {};
-		rules.forEach(rule => {
+		rules.forEach((rule) => {
 			const category = rule.category || "other";
 			if (!(category in categories)) {
 				categories[category] = [];

docs/dgeni/schema/index.js

@@ -7,11 +7,15 @@ module.exports = new Package("schema", [])
 	.processor(require("./processors/copy-schema-processor"))
 	.factory(require("./services/copy-schema"))
 
-	.config(function(computeIdsProcessor, computePathsProcessor, templateFinder) {
+	.config(function (
+		computeIdsProcessor,
+		computePathsProcessor,
+		templateFinder
+	) {
 		templateFinder.templateFolders.push(path.resolve(packagePath, "templates"));
 		computeIdsProcessor.idTemplates.push({
 			docTypes: ["schema"],
-			getAliases: function(doc) {
+			getAliases: function (doc) {
 				return [doc.id, doc.name];
 			},
 		});

docs/dgeni/tag-defs/category.js

-module.exports = function() {
+module.exports = function () {
 	return {
 		name: "category",
 	};

docs/dgeni/tag-defs/summary.js

-module.exports = function() {
+module.exports = function () {
 	return {
 		name: "summary",
 	};

docs/guide/metadata/inheritance.md

@@ -39,3 +39,5 @@ When inheriting you can still override any properties from the inherited element
 		For instance <code>&lt;input&gt;</code> is a <code>void</code> element but custom elements cannot be pure <code>void</code> thus if you inherit from it you must set <code>void</code> to <code>false</code>.
 	</p>
 </div>
+
+Inheritance is implied when overwriting existing elements, e.g. when overwriting builtin elements or loading multiple definitions of the same component.

docs/usage/cypress.md

@@ -20,7 +20,7 @@ In `cypress/plugins/index.js`:
 ```js
 const htmlvalidate = require("cypress-html-validate/dist/plugin");
 
-module.exports = on => {
+module.exports = (on) => {
   htmlvalidate.install(on);
 };
 ```

package.json

 {
   "name": "html-validate",
-  "version": "2.18.1",
+  "version": "2.19.0",
   "description": "html linter",
   "keywords": [
     "html",
@@ -47,8 +47,8 @@
     "eslint": "eslint --ext js,ts .",
     "eslint:fix": "eslint --ext js,ts . --fix",
     "htmlvalidate": "./bin/html-validate.js",
-    "prettier:check": "prettier '**/*.{ts,js,json,md,scss}' --list-different",
-    "prettier:write": "prettier '**/*.{ts,js,json,md,scss}' --write",
+    "prettier:check": "prettier . --check",
+    "prettier:write": "prettier . --write",
     "semantic-release": "semantic-release",
     "start": "grunt connect",
     "test": "jest --ci"
@@ -95,10 +95,10 @@
     "@babel/core": "7.9.0",
     "@babel/preset-env": "7.9.0",
     "@commitlint/cli": "8.3.5",
-    "@html-validate/commitlint-config": "1.0.1",
-    "@html-validate/eslint-config": "1.1.4",
+    "@html-validate/commitlint-config": "1.0.2",
+    "@html-validate/eslint-config": "1.2.0",
     "@html-validate/prettier-config": "1.0.0",
-    "@html-validate/semantic-release-config": "1.0.11",
+    "@html-validate/semantic-release-config": "1.0.12",
     "@types/babel__code-frame": "7.0.1",
     "@types/estree": "0.0.44",
     "@types/glob": "7.1.1",
@@ -136,9 +136,9 @@
     "jquery": "3.4.1",
     "lint-staged": "10.0.8",
     "load-grunt-tasks": "5.1.0",
-    "marked": "0.8.1",
+    "marked": "0.8.2",
     "minimatch": "3.0.4",
-    "prettier": "1.19.1",
+    "prettier": "2.0.2",
     "sass": "1.26.3",
     "semantic-release": "17.0.4",
     "serve-static": "1.14.1",

src/cli/__mocks__/glob.ts

@@ -30,11 +30,11 @@ function syncMock(pattern: string, options: Options = {}): string[] {
 	let src = mockFiles;
 	if (dir) {
 		src = src
-			.filter(cur => cur.startsWith(dir))
-			.map(cur => cur.slice(dir.length));
+			.filter((cur) => cur.startsWith(dir))
+			.map((cur) => cur.slice(dir.length));
 	}
 
-	return src.filter(cur => minimatch(cur, pattern));
+	return src.filter((cur) => minimatch(cur, pattern));
 }
 
 glob.setMockFiles = setMockFiles;

src/cli/expand-files.ts

@@ -59,7 +59,7 @@ export function expandFiles(
 					[directoryPattern(extensions)],
 					Object.assign({}, options, { cwd: fullpath })
 				);
-				result = result.concat(dir.map(cur => path.join(filename, cur)));
+				result = result.concat(dir.map((cur) => path.join(filename, cur)));
 				continue;
 			}
 

src/cli/formatter.ts

@@ -25,7 +25,7 @@ function wrap(
 }
 
 export function getFormatter(formatters: string): (report: Report) => string {
-	const fn: WrappedFormatter[] = formatters.split(",").map(cur => {
+	const fn: WrappedFormatter[] = formatters.split(",").map((cur) => {
 		const [name, dst] = cur.split("=", 2);
 		const moduleName = name.replace(/[^a-z]+/g, "");
 		/* eslint-disable-next-line import/no-dynamic-require */

src/cli/html-validate.ts

@@ -289,10 +289,10 @@ try {
 	} else if (mode === Mode.INIT) {
 		cli
 			.init(process.cwd())
-			.then(result => {
+			.then((result) => {
 				console.log(`Configuration written to "${result.filename}"`);
 			})
-			.catch(err => {
+			.catch((err) => {
 				if (err) {
 					console.error(err);
 				}

src/cli/init.ts

@@ -44,7 +44,7 @@ function addFrameworks(src: ConfigData, frameworks: string[]): ConfigData {
 
 function writeConfig(dst: string, config: ConfigData): Promise<void> {
 	return new Promise((resolve, reject) => {
-		fs.writeFile(dst, JSON.stringify(config, null, 2), err => {
+		fs.writeFile(dst, JSON.stringify(config, null, 2), (err) => {
 			if (err) reject(err);
 			resolve();
 		});

src/config/config-loader.spec.ts

@@ -218,7 +218,7 @@ describe("ConfigLoader", () => {
 			];
 			const data = src.get();
 			data.rules = Object.keys(data.rules)
-				.filter(key => whitelisted.includes(key))
+				.filter((key) => whitelisted.includes(key))
 				.reduce((dst, key) => {
 					dst[key] = data.rules[key];
 					return dst;

src/config/config.ts

@@ -547,7 +547,7 @@ export class Config {
 		}
 
 		/* try to match an unnamed transformer from plugin */
-		const plugin = this.plugins.find(cur => cur.name === name);
+		const plugin = this.plugins.find((cur) => cur.name === name);
 		if (plugin) {
 			return this.getUnnamedTransformerFromPlugin(name, plugin);
 		}
@@ -566,7 +566,7 @@ export class Config {
 		pluginName: string,
 		key: string
 	): Transformer {
-		const plugin = this.plugins.find(cur => cur.name === pluginName);
+		const plugin = this.plugins.find((cur) => cur.name === pluginName);
 		if (!plugin) {
 			throw new ConfigError(`No plugin named "${pluginName}" has been loaded`);
 		}

src/dom/domnode.ts

@@ -52,7 +52,7 @@ export class DOMNode {
 	 * Get the text (recursive) from all child nodes.
 	 */
 	public get textContent(): string {
-		return this.childNodes.map(node => node.textContent).join("");
+		return this.childNodes.map((node) => node.textContent).join("");
 	}
 
 	public append(node: DOMNode): void {

src/dom/htmlelement.ts

@@ -42,7 +42,7 @@ export class HtmlElement extends DOMNode {
 		this.attr = {};
 		this.metaElement = meta;
 		this.closed = closed;
-		this.voidElement = meta ? meta.void : false;
+		this.voidElement = meta ? Boolean(meta.void) : false;
 		this.depth = 0;
 		this.annotation = null;
 
@@ -113,7 +113,7 @@ export class HtmlElement extends DOMNode {
 	 */
 	public get childElements(): HtmlElement[] {
 		return this.childNodes.filter(
-			node => node.nodeType === NodeType.ELEMENT_NODE
+			(node) => node.nodeType === NodeType.ELEMENT_NODE
 		) as HtmlElement[];
 	}
 
@@ -164,8 +164,8 @@ export class HtmlElement extends DOMNode {
 
 			const parent = cur.parent;
 			const child = parent.childElements;
-			const index = child.findIndex(it => it.unique === cur.unique);
-			const numOfType = child.filter(it => it.is(cur.tagName)).length;
+			const index = child.findIndex((it) => it.unique === cur.unique);
+			const numOfType = child.filter((it) => it.is(cur.tagName)).length;
 			const solo = numOfType === 1;
 
 			/* if this is the only tagName in this level of siblings nth-child isn't needed */
@@ -376,8 +376,8 @@ export class HtmlElement extends DOMNode {
 			return new DOMTokenList(null);
 		}
 		const classes = this.getAttribute("class", true)
-			.filter(attr => attr.isStatic)
-			.map(attr => attr.value)
+			.filter((attr) => attr.isStatic)
+			.map((attr) => attr.value)
 			.join(" ");
 		return new DOMTokenList(classes);
 	}
@@ -394,12 +394,12 @@ export class HtmlElement extends DOMNode {
 	}
 
 	public get previousSibling(): HtmlElement {
-		const i = this.siblings.findIndex(node => node.unique === this.unique);
+		const i = this.siblings.findIndex((node) => node.unique === this.unique);
 		return i >= 1 ? this.siblings[i - 1] : null;
 	}
 
 	public get nextSibling(): HtmlElement {
-		const i = this.siblings.findIndex(node => node.unique === this.unique);
+		const i = this.siblings.findIndex((node) => node.unique === this.unique);
 		return i <= this.siblings.length - 2 ? this.siblings[i + 1] : null;
 	}
 

src/dom/pseudoclass/nth-child.ts

@@ -10,7 +10,7 @@ function getNthChild(node: HtmlElement): number {
 
 	if (!cache[node.unique]) {
 		const parent = node.parent;
-		const index = parent.childElements.findIndex(cur => {
+		const index = parent.childElements.findIndex((cur) => {
 			return cur.unique === node.unique;
 		});
 		cache[node.unique] = index + 1; /* nthChild starts at 1 */

src/dom/selector.ts

@@ -183,7 +183,7 @@ export class Selector {
 			case Combinator.DESCENDANT:
 				return root.getElementsByTagName(pattern.tagName);
 			case Combinator.CHILD:
-				return root.childElements.filter(node => node.is(pattern.tagName));
+				return root.childElements.filter((node) => node.is(pattern.tagName));
 			case Combinator.ADJACENT_SIBLING:
 				return Selector.findAdjacentSibling(root);
 			case Combinator.GENERAL_SIBLING:
@@ -196,7 +196,7 @@ export class Selector {
 
 	private static findAdjacentSibling(node: HtmlElement): HtmlElement[] {
 		let adjacent = false;
-		return node.siblings.filter(cur => {
+		return node.siblings.filter((cur) => {
 			if (adjacent) {
 				adjacent = false;
 				return true;
@@ -210,7 +210,7 @@ export class Selector {
 
 	private static findGeneralSibling(node: HtmlElement): HtmlElement[] {
 		let after = false;
-		return node.siblings.filter(cur => {
+		return node.siblings.filter((cur) => {
 			if (after) {
 				return true;
 			}

src/engine/engine.ts

@@ -102,7 +102,7 @@ export class Engine<T extends Parser = Parser> {
 		parser.on("*", (event, data) => {
 			lines.push({ event, data });
 		});
-		source.forEach(src => parser.parseHtml(src));
+		source.forEach((src) => parser.parseHtml(src));
 		return lines;
 	}
 
@@ -195,9 +195,9 @@ export class Engine<T extends Parser = Parser> {
 	): void {
 		const rules = event.data
 			.split(",")
-			.map(name => name.trim())
-			.map(name => allRules[name])
-			.filter(rule => rule); /* filter out missing rules */
+			.map((name) => name.trim())
+			.map((name) => allRules[name])
+			.filter((rule) => rule); /* filter out missing rules */
 		switch (event.action) {
 			case "enable":
 				this.processEnableDirective(rules, parser);
@@ -231,7 +231,7 @@ export class Engine<T extends Parser = Parser> {
 
 		/* enable rules on node */
 		parser.on("tag:open", (event: string, data: TagOpenEvent) => {
-			data.target.enableRules(rules.map(rule => rule.name));
+			data.target.enableRules(rules.map((rule) => rule.name));
 		});
 	}
 
@@ -242,7 +242,7 @@ export class Engine<T extends Parser = Parser> {
 
 		/* disable rules on node */
 		parser.on("tag:open", (event: string, data: TagOpenEvent) => {
-			data.target.disableRules(rules.map(rule => rule.name));
+			data.target.disableRules(rules.map((rule) => rule.name));
 		});
 	}
 
@@ -262,7 +262,7 @@ export class Engine<T extends Parser = Parser> {
 
 				/* disable rules directly on the node so it will be recorded for later,
 				 * more specifically when using the domtree to trigger errors */
-				data.target.disableRules(rules.map(rule => rule.name));
+				data.target.disableRules(rules.map((rule) => rule.name));
 			}
 		);
 
@@ -298,7 +298,7 @@ export class Engine<T extends Parser = Parser> {
 		const unregister = parser.on(
 			"tag:open",
 			(event: string, data: TagOpenEvent) => {
-				data.target.disableRules(rules.map(rule => rule.name));
+				data.target.disableRules(rules.map((rule) => rule.name));
 			}
 		);
 

src/event/eventhandler.ts

@@ -59,7 +59,7 @@ export class EventHandler {
 			this.listeners[event] || [],
 			this.listeners["*"] || []
 		);
-		callbacks.forEach(listener => {
+		callbacks.forEach((listener) => {
 			listener.call(null, event, data);
 		});
 	}

src/formatters/checkstyle.ts

@@ -33,12 +33,12 @@ export default function checkstyleFormatter(results: Result[]): string {
 	output += `<?xml version="1.0" encoding="utf-8"?>`;
 	output += `<checkstyle version="4.3">`;
 
-	results.forEach(result => {
+	results.forEach((result) => {
 		const messages = result.messages;
 
 		output += `<file name="${xmlescape(result.filePath)}">`;
 
-		messages.forEach(message => {
+		messages.forEach((message) => {
 			const ruleId = message.ruleId
 				? xmlescape(`htmlvalidate.rules.${message.ruleId}`)
 				: "";

src/formatters/codeframe.ts

@@ -142,13 +142,13 @@ export default function codeframe(results: Result[]): string {
 	let warnings = 0;
 
 	const resultsWithMessages = results.filter(
-		result => result.messages.length > 0
+		(result) => result.messages.length > 0
 	);
 
 	let output = resultsWithMessages
 		.reduce((resultsOutput, result) => {
 			const messages = result.messages.map(
-				message => `${formatMessage(message, result)}\n\n`
+				(message) => `${formatMessage(message, result)}\n\n`
 			);
 
 			errors += result.errorCount;

src/formatters/text.ts

@@ -5,7 +5,7 @@ export default function textFormatter(results: Result[]): string {
 	let output = "";
 	let total = 0;
 
-	results.forEach(result => {
+	results.forEach((result) => {
 		const messages = result.messages;
 
 		if (messages.length === 0) {
@@ -15,7 +15,7 @@ export default function textFormatter(results: Result[]): string {
 		total += messages.length;
 
 		output += messages
-			.map(message => {
+			.map((message) => {
 				let messageType;
 
 				if (message.severity === 2) {

src/htmlvalidate.ts

@@ -97,7 +97,7 @@ class HtmlValidate {
 	 */
 	public validateMultipleFiles(filenames: string[]): Report {
 		return Reporter.merge(
-			filenames.map(filename => this.validateFile(filename))
+			filenames.map((filename) => this.validateFile(filename))
 		);
 	}
 
@@ -185,7 +185,7 @@ class HtmlValidate {
 			if (source.transformedBy) {
 				result.push("Transformed by:");
 				result = result.concat(
-					source.transformedBy.reverse().map(name => ` - ${name}`)
+					source.transformedBy.reverse().map((name) => ` - ${name}`)
 				);
 			}
 			if (source.hooks && Object.keys(source.hooks).length > 0) {

src/matchers.ts

@@ -117,7 +117,7 @@ function toHaveErrors(
 	errors: Array<[string, string] | {}>
 ): jest.CustomMatcherResult {
 	const actual = flattenMessages(report);
-	const matcher = errors.map(entry => {
+	const matcher = errors.map((entry) => {
 		if (Array.isArray(entry)) {
 			const [ruleId, message] = entry;
 			return expect.objectContaining({ ruleId, message });
@@ -170,7 +170,7 @@ function toHTMLValidate(
 		return { pass, message: () => "HTML is valid when an error was expected" };
 	} else {
 		const errors = report.results[0].messages.map(
-			message => `  ${message.message} [${message.ruleId}]`
+			(message) => `  ${message.message} [${message.ruleId}]`
 		);
 		return {
 			pass,

src/meta/table.spec.ts

@@ -406,6 +406,29 @@ describe("MetaTable", () => {
 			);
 		});
 
+		it("should be implied when a previous element of the same name exists", () => {
+			expect.assertions(1);
+			const table = new MetaTable();
+			table.loadFromObject({
+				foo: {
+					flow: true,
+				},
+			});
+			table.loadFromObject({
+				foo: {
+					phrasing: true,
+				},
+			});
+			const foo = table.getMetaFor("foo");
+			expect(foo).toEqual(
+				expect.objectContaining({
+					tagName: "foo",
+					flow: true,
+					phrasing: true,
+				})
+			);
+		});
+
 		it("should allow overriding", () => {
 			expect.assertions(1);
 			const table = new MetaTable();
@@ -429,6 +452,64 @@ describe("MetaTable", () => {
 			);
 		});
 
+		it("should merge objects", () => {
+			expect.assertions(2);
+			const table = new MetaTable();
+			table.loadFromObject({
+				foo: {
+					attributes: {
+						a: ["1"],
+						b: ["1"],
+						c: ["1"],
+					},
+				},
+				bar: {
+					inherit: "foo",
+					attributes: {
+						b: ["2"],
+						c: null,
+					},
+				},
+			});
+			table.loadFromObject({
+				foo: {
+					attributes: {
+						a: ["2"],
+						b: null,
+					},
+				},
+			});
+			const foo = table.getMetaFor("foo");
+			const bar = table.getMetaFor("bar");
+			expect(foo).toMatchInlineSnapshot(`
+				Object {
+				  "attributes": Object {
+				    "a": Array [
+				      "2",
+				    ],
+				    "c": Array [
+				      "1",
+				    ],
+				  },
+				  "tagName": "foo",
+				}
+			`);
+			expect(bar).toMatchInlineSnapshot(`
+				Object {
+				  "attributes": Object {
+				    "a": Array [
+				      "1",
+				    ],
+				    "b": Array [
+				      "2",
+				    ],
+				  },
+				  "inherit": "foo",
+				  "tagName": "bar",
+				}
+			`);
+		});
+
 		it("should throw error when extending missing element", () => {
 			expect.assertions(1);
 			const table = new MetaTable();

src/meta/table.ts

@@ -37,12 +37,16 @@ function clone(src: any): any {
 	return JSON.parse(JSON.stringify(src));
 }
 
+function overwriteMerge<T>(a: T[], b: T[]): T[] {
+	return b;
+}
+
 /**
  * AJV keyword "regexp" to validate the type to be a regular expression.
  * Injects errors with the "type" keyword to give the same output.
  */
 /* istanbul ignore next: manual testing */
-const ajvRegexpValidate: Ajv.ValidateFunction = function(
+const ajvRegexpValidate: Ajv.ValidateFunction = function (
 	data: any,
 	dataPath: string
 ): boolean {
@@ -177,10 +181,7 @@ export class MetaTable {
 	}
 
 	private addEntry(tagName: string, entry: MetaData): void {
-		const defaultEntry = {
-			void: false,
-		};
-		let parent = {};
+		let parent = this.elements[tagName] || {};
 
 		/* handle inheritance */
 		if (entry.inherit) {
@@ -194,9 +195,11 @@ export class MetaTable {
 		}
 
 		/* merge all sources together */
-		const expanded: MetaElement = Object.assign(defaultEntry, parent, entry, {
-			tagName,
-		}) as MetaElement;
+		const expanded: MetaElement = deepmerge(
+			parent,
+			{ ...entry, tagName },
+			{ arrayMerge: overwriteMerge }
+		);
 		expandRegex(expanded);
 
 		this.elements[tagName] = expanded;
@@ -269,7 +272,11 @@ function expandRegexValue(value: string | RegExp): string | RegExp {
 function expandRegex(entry: MetaElement): void {
 	if (!entry.attributes) return;
 	for (const [name, values] of Object.entries(entry.attributes)) {
-		entry.attributes[name] = values.map(expandRegexValue);
+		if (values) {
+			entry.attributes[name] = values.map(expandRegexValue);
+		} else {
+			delete entry.attributes[name];
+		}
 	}
 }
 
@@ -327,7 +334,7 @@ function matchAttribute(node: HtmlElement, match: any): boolean {
 			`Property expression "matchAttribute" must take [key, op, value] array as argument when evaluating metadata for <${node.tagName}>`
 		);
 	}
-	const [key, op, value] = match.map(x => x.toLowerCase());
+	const [key, op, value] = match.map((x) => x.toLowerCase());
 	const nodeValue = (node.getAttributeValue(key) || "").toLowerCase();
 	switch (op) {
 		case "!=":

src/meta/validator.ts

@@ -29,7 +29,7 @@ export class Validator {
 		if (!rules) {
 			return true;
 		}
-		return rules.some(rule => {
+		return rules.some((rule) => {
 			return Validator.validatePermittedRule(node, rule);
 		});
 	}
@@ -54,7 +54,7 @@ export class Validator {
 		if (!rules) {
 			return true;
 		}
-		const category = rules.find(cur => {
+		const category = rules.find((cur) => {
 			/** @todo handle complex rules and not just plain arrays (but as of now
 			 * there is no use-case for it) */
 			// istanbul ignore next
@@ -133,7 +133,7 @@ export class Validator {
 			return true;
 		}
 
-		return rules.some(rule => node.closest(rule));
+		return rules.some((rule) => node.closest(rule));
 	}
 
 	/**
@@ -152,8 +152,8 @@ export class Validator {
 			return [];
 		}
 
-		return rules.filter(tagName => {
-			const haveMatchingChild = node.childElements.some(child =>
+		return rules.filter((tagName) => {
+			const haveMatchingChild = node.childElements.some((child) =>
 				child.is(tagName)
 			);
 			return !haveMatchingChild;

src/parser/__snapshots__/parser.spec.ts.snap

@@ -32,7 +32,6 @@ Object {
     "dd",
   ],
   "tagName": "i",
-  "void": false,
 }
 `;
 
@@ -67,6 +66,5 @@ Object {
   ],
   "phrasing": true,
   "tagName": "u",
-  "void": false,
 }
 `;

src/parser/parser.spec.ts

@@ -1010,7 +1010,7 @@ describe("parser", () => {
 
 		it("attribute (deprecated method)", () => {
 			expect.assertions(5);
-			const processAttribute = jest.fn(attr => {
+			const processAttribute = jest.fn((attr) => {
 				attr.key = "fred";
 				attr.value = "barney";
 				return attr;
@@ -1054,7 +1054,7 @@ describe("parser", () => {
 			it("by calling hook", () => {
 				expect.assertions(2);
 				let context: any;
-				const processElement = jest.fn(function(this: any) {
+				const processElement = jest.fn(function (this: any) {
 					context = this;
 				});
 				const source: Source = {

src/plugin/plugin.spec.ts

@@ -192,7 +192,6 @@ describe("Plugin", () => {
 			expect(meta).toEqual({
 				tagName: "my-element",
 				myMeta: 5,
-				void: false,
 			});
 		});
 
@@ -225,7 +224,6 @@ describe("Plugin", () => {
 			expect(meta).toEqual({
 				tagName: "my-element",
 				myMeta: 5,
-				void: false,
 			});
 		});
 
@@ -280,7 +278,6 @@ describe("Plugin", () => {
 				tagName: "my-element",
 				foo: "copied" /* foo is marked for copying */,
 				bar: "original" /* bar is not marked for copying */,
-				void: false /* autofilled */,
 			});
 		});
 	});

src/reporter.spec.ts

@@ -43,14 +43,16 @@ describe("Reporter", () => {
 			]);
 			expect(merged.results).toHaveLength(2);
 			expect(merged.results[0].filePath).toEqual("foo");
-			expect(merged.results[0].messages.map(x => x.message)).toEqual([
+			expect(merged.results[0].messages.map((x) => x.message)).toEqual([
 				"fred",
 				"barney",
 				"wilma",
 			]);
 			expect(merged.results[0].errorCount).toEqual(3);
 			expect(merged.results[1].filePath).toEqual("bar");
-			expect(merged.results[1].messages.map(x => x.message)).toEqual(["spam"]);
+			expect(merged.results[1].messages.map((x) => x.message)).toEqual([
+				"spam",
+			]);
 			expect(merged.results[1].errorCount).toEqual(1);
 			expect(merged.errorCount).toEqual(4);
 			expect(merged.warningCount).toEqual(0);
@@ -218,7 +220,7 @@ describe("Reporter", () => {
 function createResult(filename: string, messages: string[]): Result {
 	return {
 		filePath: filename,
-		messages: messages.map(cur => createMessage(cur)),
+		messages: messages.map((cur) => createMessage(cur)),
 		errorCount: messages.length,
 		warningCount: 0,
 	};

src/reporter.ts

@@ -75,7 +75,7 @@ export class Reporter {
 	 * Merge two or more reports into a single one.
 	 */
 	public static merge(reports: Report[]): Report {
-		const valid = reports.every(report => report.valid);
+		const valid = reports.every((report) => report.valid);
 		const merged: { [key: string]: Result } = {};
 		reports.forEach((report: Report) => {
 			report.results.forEach((result: Result) => {
@@ -138,7 +138,7 @@ export class Reporter {
 	public save(sources?: Source[]): Report {
 		const report: Report = {
 			valid: this.isValid(),
-			results: Object.keys(this.result).map(filePath => {
+			results: Object.keys(this.result).map((filePath) => {
 				const messages = [].concat(this.result[filePath]).sort(messageSort);
 				const source = (sources || []).find(
 					(source: Source) => filePath === (source.filename ?? "")
@@ -168,11 +168,11 @@ export class Reporter {
 }
 
 function countErrors(messages: Message[]): number {
-	return messages.filter(m => m.severity === Severity.ERROR).length;
+	return messages.filter((m) => m.severity === Severity.ERROR).length;
 }
 
 function countWarnings(messages: Message[]):