Rebuilt frontmatter templates as template widgets

plug-api/lib/cheap_yaml.test.ts

@@ -1,5 +1,5 @@
 import { assertEquals } from "../../test_deps.ts";
-import { determineTags } from "./cheap_yaml.ts";
+import { determineTags, isTemplate } from "./cheap_yaml.ts";
 
 Deno.test("cheap yaml", () => {
   assertEquals([], determineTags(""));
@@ -14,3 +14,77 @@ Deno.test("cheap yaml", () => {
     determineTags(`tags:\n- "#bla"\n- template`),
   );
 });
+
+Deno.test("Test template extraction", () => {
+  assertEquals(
+    isTemplate(`---
+name: bla
+tags: template
+---
+
+Sup`),
+    true,
+  );
+
+  assertEquals(
+    isTemplate(`---
+tags: template, something else
+---
+`),
+    true,
+  );
+
+  assertEquals(
+    isTemplate(`---
+tags: something else, template
+---
+`),
+    true,
+  );
+
+  assertEquals(
+    isTemplate(`---
+tags:
+- bla
+- template
+---
+`),
+    true,
+  );
+
+  assertEquals(
+    isTemplate(`#template`),
+    true,
+  );
+
+  assertEquals(
+    isTemplate(`  #template This is a template`),
+    true,
+  );
+
+  assertEquals(
+    isTemplate(`---
+tags:
+- bla
+somethingElse:
+- template
+---
+`),
+    false,
+  );
+
+  assertEquals(
+    isTemplate(`---
+name: bla
+tags: aefe
+---
+
+Sup`),
+    false,
+  );
+
+  assertEquals(
+    isTemplate(`Sup`),
+    false,
+  );
+});

plug-api/lib/cheap_yaml.ts

@@ -34,3 +34,28 @@ export function determineTags(yamlText: string): string[] {
   }
   return tags;
 }
+
+const frontMatterRegex = /^---\n(([^\n]|\n)*?)---\n/;
+
+/**
+ * Quick and dirty way to check if a page is a template or not
+ * @param pageText
+ * @returns
+ */
+export function isTemplate(pageText: string): boolean {
+  const frontmatter = frontMatterRegex.exec(pageText);
+  // Poor man's YAML frontmatter parsing
+  if (frontmatter) {
+    pageText = pageText.slice(frontmatter[0].length);
+    const frontmatterText = frontmatter[1];
+    const tags = determineTags(frontmatterText);
+    if (tags.includes("template")) {
+      return true;
+    }
+  }
+  // Or if the page text starts with a #template tag
+  if (/^\s*#template(\W|$)/.test(pageText)) {
+    return true;
+  }
+  return false;
+}

plug-api/silverbullet-syscall/code_widget.ts

@@ -5,7 +5,7 @@ export function render(
   lang: string,
   body: string,
   pageName: string,
-): Promise<CodeWidgetContent> {
+): Promise<CodeWidgetContent | null> {
   return syscall("codeWidget.render", lang, body, pageName);
 }
 

plug-api/types.ts

@@ -127,14 +127,13 @@ export type ObjectQuery = Omit<Query, "prefix">;
 export type CodeWidgetCallback = (
   bodyText: string,
   pageName: string,
-) => Promise<CodeWidgetContent>;
+) => Promise<CodeWidgetContent | null>;
 
 export type CodeWidgetContent = {
   html?: string;
   markdown?: string;
   script?: string;
   buttons?: CodeWidgetButton[];
-  banner?: string;
 };
 
 export type CodeWidgetButton = {