first commit; migrate code from minimal/docs-server

src/async-steps.ts

@@ -0,0 +1,41 @@
+
+// marked does not support asynchronous steps in the rendering process.
+// as such, in order to support external renderers that do their processing
+// async, this handles swapping out a placeholder for the additionally processed
+// content after marked is finished rendering
+
+let next_task_id = 1;
+const data_binding = /{{@@!@!@@ MARKED ASYNC DATA BINDING PLACEHOLDER {{([0-9]+)}} @@!@!@@}}/g;
+
+const pending_tasks: Record<number, Promise<string>> = { };
+
+export function bind_data_async(data_generator: Promise<string>) {
+	const task_id = next_task_id++;
+	const placeholder = `{{@@!@!@@ MARKED ASYNC DATA BINDING PLACEHOLDER {{${task_id}}} @@!@!@@}}`;
+	pending_tasks[task_id] = data_generator;
+	return placeholder;
+}
+
+export async function resolve_async_bindings(html: string) {
+	const bindings: string[] = [ ];
+	const promises: Promise<string>[] = [ ];
+
+	let match: RegExpMatchArray;
+
+	while (match = data_binding.exec(html)) {
+		bindings.push(match[0]);
+		promises.push(pending_tasks[match[1]]);
+		delete pending_tasks[match[1]];
+	}
+
+	data_binding.lastIndex = 0;
+
+	const results = await Promise.all(promises);
+
+	for (let i = 0; i < results.length; i++) {
+		html = html.replace(bindings[i], results[i]);
+	}
+
+	return html;
+}
+