Fix #683

CHANGELOG.md

@@ -13,6 +13,7 @@ Go to the `v1` branch to see the changelog of Lume 1.
 - New plugin: `brotli` to compress files. [#681]
 - New plugin: `gzip` to compress files. [#680]
 - New `precompress` middleware, to serve precompressed files. [#664]
+- Allow to specify fallbacks for `metas` and `feed` plugins [#683].
 
 ### Fixed
 - Nav plugin: Breadcrumb with urls with CJK characters.
@@ -570,6 +571,7 @@ Go to the `v1` branch to see the changelog of Lume 1.
 [#679]: https://github.com/lumeland/lume/issues/679
 [#680]: https://github.com/lumeland/lume/issues/680
 [#681]: https://github.com/lumeland/lume/issues/681
+[#683]: https://github.com/lumeland/lume/issues/683
 
 [Unreleased]: https://github.com/lumeland/lume/compare/v2.3.3...HEAD
 [2.3.3]: https://github.com/lumeland/lume/compare/v2.3.2...v2.3.3

core/utils/data_values.ts

@@ -8,44 +8,74 @@ import type { Data } from "../file.ts";
 export function getDataValue(data: Partial<Data>, value?: unknown) {
   // Get the value from the page data
   if (typeof value === "string") {
-    if (value.startsWith("=")) {
-      const key = value.slice(1);
-
-      if (!key.includes(".")) {
-        return data[key];
-      }
-
-      const keys = key.split(".");
-      let val = data;
-      for (const key of keys) {
-        val = val?.[key];
-      }
-      return val;
+    return searchValue(data, value);
+  }
+
+  if (typeof value === "function") {
+    return value(data);
+  }
+
+  return value;
+}
+
+function searchValue(data: Partial<Data>, value: string): unknown {
+  if (!value) {
+    return;
+  }
+
+  if (value.startsWith("=")) {
+    let key = value.slice(1);
+    [key, value] = parseFallback(key);
+
+    if (!key.includes(".")) {
+      return data[key] ?? searchValue(data, value);
     }
 
-    if (value.startsWith("$")) {
-      return queryCss(value, data.page?.document);
+    const keys = key.split(".");
+    let val = data;
+    for (const key of keys) {
+      val = val?.[key];
     }
+    return val ?? searchValue(data, value);
   }
 
-  if (typeof value === "function") {
-    return value(data);
+  if (value.startsWith("$")) {
+    let selector = value.slice(1);
+    [selector, value] = parseFallback(selector);
+
+    return queryCss(selector, data.page?.document) ?? searchValue(data, value);
   }
 
   return value;
 }
 
-function queryCss(value: string, document?: Document) {
-  // https://regexr.com/7qnot
-  const checkForAttrPattern = /^\$(.+)\s+(?:attr\(([\w\-]+)\))$/;
-  const checkResult = value.match(checkForAttrPattern);
+function parseFallback(key: string): [string, string] {
+  const fallback = key.indexOf("||");
+
+  if (fallback !== -1) {
+    return [
+      key.slice(0, fallback).trim(),
+      key.slice(fallback + 2).trim(),
+    ];
+  }
+
+  return [
+    key,
+    "",
+  ];
+}
+
+// https://regexr.com/7qnot
+const checkForAttrPattern = /^(.+)\s+(?:attr\(([\w\-]+)\))$/;
+
+function queryCss(query: string, document?: Document) {
+  const checkResult = query.match(checkForAttrPattern);
 
   const hasAttr = checkResult?.[0];
   if (hasAttr) {
     const [_, query, name] = checkResult;
     return document?.querySelector(query)?.getAttribute(name);
   }
 
-  const query = value.slice(1);
   return document?.querySelector(query)?.innerHTML;
 }

tests/__snapshots__/feed.test.ts.snap

@@ -117,10 +117,10 @@ snapshot[`RSS plugin 2`] = `[]`;
 snapshot[`RSS plugin 3`] = `
 [
   {
-    content: '{"version":"https://jsonfeed.org/version/1","title":"My RSS Feed","home_page_url":"https://example.com/","feed_url":"https://example.com/feed.json","description":"","items":[{"id":"https://example.com/page5/","url":"https://example.com/page5/","title":"PAGE 5","content_html":"Content of Page 5","date_published":"Thu, 21 Jun 1979 23:45:00 GMT","date_modified":"Thu, 21 Jun 1979 23:45:00 GMT"}]}',
+    content: '{"version":"https://jsonfeed.org/version/1","title":"My RSS Feed","home_page_url":"https://example.com/","feed_url":"https://example.com/feed.json","items":[{"id":"https://example.com/page5/","url":"https://example.com/page5/","title":"PAGE 5","content_html":"Content of Page 5","date_published":"Thu, 21 Jun 1979 23:45:00 GMT","date_modified":"Thu, 21 Jun 1979 23:45:00 GMT"}]}',
     data: {
       basename: "feed",
-      content: '{"version":"https://jsonfeed.org/version/1","title":"My RSS Feed","home_page_url":"https://example.com/","feed_url":"https://example.com/feed.json","description":"","items":[{"id":"https://example.com/page5/","url":"https://example.com/page5/","title":"PAGE 5","content_html":"Content of Page 5","date_published":"Thu, 21 Jun 1979 23:45:00 GMT","date_modified":"Thu, 21 Jun 1979 23:45:00 GMT"}]}',
+      content: '{"version":"https://jsonfeed.org/version/1","title":"My RSS Feed","home_page_url":"https://example.com/","feed_url":"https://example.com/feed.json","items":[{"id":"https://example.com/page5/","url":"https://example.com/page5/","title":"PAGE 5","content_html":"Content of Page 5","date_published":"Thu, 21 Jun 1979 23:45:00 GMT","date_modified":"Thu, 21 Jun 1979 23:45:00 GMT"}]}',
       page: [
         "src",
         "data",
@@ -142,7 +142,6 @@ snapshot[`RSS plugin 3`] = `
     <title>My RSS Feed</title>
     <link>https://example.com/</link>
     <atom:link href="https://example.com/feed.rss" rel="self" type="application/rss+xml"/>
-    <description/>
     <lastBuildDate>Wed, 01 Jan 2020 00:00:00 GMT</lastBuildDate>
     <language>en</language>
     <generator>https://lume.land</generator>
@@ -164,7 +163,6 @@ snapshot[`RSS plugin 3`] = `
     <title>My RSS Feed</title>
     <link>https://example.com/</link>
     <atom:link href="https://example.com/feed.rss" rel="self" type="application/rss+xml"/>
-    <description/>
     <lastBuildDate>Wed, 01 Jan 2020 00:00:00 GMT</lastBuildDate>
     <language>en</language>
     <generator>https://lume.land</generator>
@@ -225,7 +223,7 @@ snapshot[`RSS plugin 3`] = `
   },
   {
     content: "<!DOCTYPE html>
-Content of Page 5",
+<html><head></head><body>Content of Page 5</body></html>",
     data: {
       basename: "page5",
       children: "Content of Page 5",

tests/feed.test.ts

@@ -16,8 +16,8 @@ Deno.test("RSS plugin", async (t) => {
       },
       items: {
         title: (data) => data.title?.toUpperCase(),
-        updated: "=date",
-        published: "=published",
+        updated: "=date || $.date",
+        published: "$.not-found || =published",
       },
     }),
   );