fix: fix API build for composite components (#391)

Background: some of the components do not have separate sample page, but they are appended to others sample page. The API of those components is part (in most cases) of parent components API, that use them as composite components.
Issue: the API of the composite/child components misses base properties.
Root cause: the API generation of the parent component is done before the API generation of the composite/child components.
Solution: calculate the API of those composite components before their addition to parents` component API.
Before (StandardListItem "selected" and "type" properties are missing)

lib/documentation/index.js

@@ -34,7 +34,6 @@ Handlebars.registerHelper('toKebabCase', function (str) {
 	return kebab !== str ? kebab : "";
 });
 
-
 Handlebars.registerHelper('checkEven', function (iIndex) {
 	return (iIndex % 2 === 0) ? "api-table-roll-even" : "api-table-roll-odd";
 });
@@ -46,35 +45,48 @@ Handlebars.registerPartial('methods', methodsTemplate);
 
 mkdirp(`dist/test-resources/sap/ui/webcomponents/main/api`);
 
-entries.forEach((entry, index) => {
+let entriesAPI = [];
 
-	const parentName = entry.extends;
-	let parent = getComponentByName(parentName) || {};
+const mergeParentAPI = entry => {
+	if (entriesAPI.indexOf(entry.basename) !== -1) {
+		return entry;
+	}
 
+	let parent = getComponentByName(entry.extends) || {};
 	parent = { ...{ properties: [], events: [], slots: [] }, ...parent };
 
 	// extend component documentation
 	entry.properties = [...(entry.properties || []), ...(parent.properties || [])];
 	entry.events = [...(entry.events || []), ...(parent.events || [])];
 	entry.slots = [...(entry.slots || []), ...(parent.slots || [])];
 
+	entriesAPI.push(entry.basename);
+
+	return entry;
+}
+
+const appendAdditionalEntriesAPI = entry => {
 	if (entry.appenddocs) {
 		const additionalEntries = entry.appenddocs.split(" ");
-
 		entry.additionalDocs = [];
 
 		additionalEntries.forEach(entryName => {
-			entry.additionalDocs.push(getComponentByName(entryName));
+			let additionalEntry = getComponentByName(entryName);
+			additionalEntry = mergeParentAPI(additionalEntry);
+			entry.additionalDocs.push(additionalEntry);
 		});
 	}
 
+	return entry;
+}
+
+const generateSamplePage = entry => {
 	let content = "";
 
 	try {
 		content = fs.readFileSync(`dist/test-resources/sap/ui/webcomponents/main/samples/${capitalize(entry.basename)}.sample.html`, 'utf8');
 	} catch (err) { }
 
-
 	if (content) {
 		const fnRedirect = `
 		<script>
@@ -105,5 +117,18 @@ entries.forEach((entry, index) => {
 			// console.log(err);
 		});
 	}
+}
+
+const generateComponentAPI = entry => {
+	// (1) merge parent API
+	entry = mergeParentAPI(entry);
+
+	// (2) append additional API for children
+	entry = appendAdditionalEntriesAPI(entry);
+
+	// (3) generate sample page
+	generateSamplePage(entry);
+}
 
-});
+entries.forEach(generateComponentAPI);
+entriesAPI = [];