feat: HTML node (#5107)

* ✨ Create HTML templating node PoC

* ♻️ Apply feedback

* 🐛 Scope CSS selectors

* ✏️ Adjust description

* ✏️ Adjust placeholder

* ⚡ Replace two custom files with package output

* ➕ Add `codemirror-lang-html-n8n`

* 👕 Appease linter

* 🧪 Skip event bus tests

* ⏪ Revert "Skip event bus tests"

This reverts commit 5702585d0de3b8465660567132e9003e78f1104c.

* ✏️ Update codex

* 🧹 Cleanup

* 🐛 Restore original for `continueOnFail`

* ⚡ Improve `getResolvables`

packages/nodes-base/nodes/Html/utils.ts

@@ -0,0 +1,46 @@
+import type { IDataObject } from 'n8n-workflow';
+import type { IValueData, Cheerio } from './types';
+
+/**
+ * @TECH_DEBT Explore replacing with handlebars
+ */
+export function getResolvables(html: string) {
+	if (!html) return [];
+
+	const resolvables = [];
+	const resolvableRegex = /({{[\s\S]*?}})/g;
+
+	let match;
+
+	while ((match = resolvableRegex.exec(html)) !== null) {
+		if (match[1]) {
+			resolvables.push(match[1]);
+		}
+	}
+
+	return resolvables;
+}
+
+// The extraction functions
+const extractFunctions: {
+	[key: string]: ($: Cheerio, valueData: IValueData) => string | undefined;
+} = {
+	attribute: ($: Cheerio, valueData: IValueData): string | undefined =>
+		$.attr(valueData.attribute!),
+	// eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
+	html: ($: Cheerio, _valueData: IValueData): string | undefined => $.html() || undefined,
+	text: ($: Cheerio, _valueData: IValueData): string | undefined => $.text(),
+	value: ($: Cheerio, _valueData: IValueData): string | undefined => $.val(),
+};
+
+/**
+ * Simple helper function which applies options
+ */
+export function getValue($: Cheerio, valueData: IValueData, options: IDataObject) {
+	const value = extractFunctions[valueData.returnValue]($, valueData);
+	if (options.trimValues === false || value === undefined) {
+		return value;
+	}
+
+	return value.trim();
+}